Western Toad - Anaxyrus boreas
State Rank Reason (see State Rank above)
Over the last few decades this species has undergone serious declines in abundance due primarily to infection with Chytrid fungus. While declines in breeding site occupancy appear to have stabilized in the last decade, changes to abundance across the species range within Montana remain unknown. Significant threats to the persistence of this species remain from continued impacts of disease and mortality of adults and young during breeding and local migration.
- Details on Status Ranking and Review
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment142,183 square Kilometers from Natural Heritage Program range maps
ScoreB - Large Decline (decline of 75-90%)
CommentVery few sites in drainages with suitable habitat are occupied. State populations are thought to have declined precipitously in the 1980s, possibly due to Chytrid fungus. Robust baseline data are not available to estimate the decline in abundance, but given that < 5% of seemingly suitable breeding sites are used within range and often by relatively few individuals, declines of up to 90% seem reasonable.
ScoreU/E - Unknown, but believed to be stable with population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentSurveys of known breeding locations across the Montana range did not find a difference from 2003-2005 surveys in the proportion of sites with evidence of breeding. Declines may have stabilized. However, this metric does not assess abundance, and changes in the number of animals using a site or area is possible.
ScoreA - Substantial, imminent threat. Threat is moderate to severe and imminent for most (>60%) of the population or area.
CommentFurther declines in abundance due to disease, vehicle caused mortalities on roads in proximity to migratory corridors and/or breeding sites
SeverityHigh - Loss of species population (all individuals) or destruction of species habitat in area affected, with effects essentially irreversible or requiring long-term recovery (>100 years).
CommentIf disease continues to impact populations, long term recovery could exceed 50 years if it is reversible with the continued presence of the chytrid pathogen. Declines may have isolated extant populations, requiring significant recovery to reconnect these
ScopeHigh - > 60% of total population or area affected
CommentAll of the species range is under threat
ImmediacyHigh - Threat is operational (happening now) or imminent (within a year).
CommentThreats are ongoing
ScoreB - Moderately Vulnerable. Species exhibits moderate age of maturity, frequency of reproduction, and/or fecundity such that populations generally tend to recover from decreases in abundance over a period of several years (on the order of 5-20 years or 2-5 generations); or species has moderate dispersal capability such that extirpated populations generally become reestablished through natural recolonization (unaided by humans).
CommentSlow maturation but can have high fecundity but low juvenile survival
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentSpecies needs lentic waterbodies to breed
Raw Conservation Status Score
3.5 + 0 (geographic distribution) + 0 (environmental specificity) + -0.25 (long-term trend) + -1 (threats) = 2.25
Laid in long strings that are one to three (usually two) eggs wide in a zigzag pattern and contain 1,000 to more than 18,000 eggs (usually 6,000 to 12,000) (Livezey and Wright 1947, Samallow 1980, Olson 1988, Carey et al. 2000). Each ovum is black above, white below, and is surrounded by two jelly layers. Ovum diameters are 1.5 to 1.8 mm, but total egg diameters, including both jelly layers, are approximately 5 to 6.8 mm (Livezey and Wright 1947, Karlstrom 1962a, Maxell et al. 2002). In Montana, clutch size has been documented at 20,469 eggs in a 30 cm strand of two jelly layers. Egg were reported hatching in less than 7 days (Maxell et al. 2002).
Body and tail musculature are black or dark brown with either a black or gray belly (Maxell et al. 2009). The tail fins are both clear with dendritic pigmentation, with the dorsal tail fin having more pigmentation (Maxell et al. 2009). The anus is on the midline at the front end of the ventral tail fin. The eyes about midway between the dorsal midline and edge of the head. Labial tooth rows are 2/3, oral papillae are restricted to the sides of the mouth. Total length (TL) of 10-38 mm (Carpenter 1953, Corkran and Thoms 2006).
JUVENILES AND ADULTS
The skin is dry with a dorsal base color of olive green or light or dark brown with reddish or light brown color on the warts and small black spots over everything (Maxell et al. 2009). The warts may be reddish-brown and encircled by dark pigment. Ventral color is cream to tan mottled with numerous dark blotches. A white stripe extends down the center of the back in older individuals but may be absent or inconspicuous in juveniles (Maxell et al. 2009). Parotid glands are oval and larger than the eyes, located behind the eye and tympanum. Cranial crests are absent or indistinct. The eyes have horizontal pupils. The hind feet each have two light brown digging “spades” on their soles, but the spades lack a sharp cutting edge (Black 1970b, Maxell et al. 2009). Mature males have a dark patch on the inner surface of the innermost digit ("thumb") during breeding. Males lack a vocal sac; however, they may produce a repeated chirping sound. Snout-vent length (SVL) of 11-118 mm; with males rarely exceeding 95 mm SVL and females rarely 110 mm (Black 1970b, Maxell et al. 2009). Recently metamorphosed toadlets measure about 10 to 16 mm SVL but can be 16 to 20 mm (Maxell et al. 2002). Juveniles 20 to 35 mm SVL often are present in wetlands adjacent to breeding sites (Nussbaum et al. 1983, Hammerson 1999).
Adult Western Toad lack the prominent cranial crests found on the other species of Montana toads. The Woodhouse’s Toad (Anaxyrus woodhousii
) have parallel cranial crests on the snout and behind the eyes in the shape of an “L”. Western Toad have horizontal rather than vertical pupils. Eggs and larvae of Western Toad tadpoles lack visible white or gold flecks on the back that are present in Woodhouse's and Great Plains Toad (Anaxyrus cognatus
) tadpoles (Werner et al. 2004). Woodhouse's Toad ova are enclosed in a single jelly layer, not two, and Great Plains Toad eggs are in strings that are noticeably pinched between each egg (Bragg 1937a). However, eggs and tadpoles of Western and Woodhouse's Toads are very similar and may be indistinguishable in some cases. Distribution is a useful character for all life stages. The geographic range of Great Plains Toad does not overlap with the geographic range of Western Toad. See the geographic range of Woodhouse’s Toad for limited areas of possible overlap in a narrow area north of the Beartooth and Absaroka mountains (Maxell et al. 2003).
Western Hemisphere Range
The Western Toad is currently recognized as two subspecies that range from the Rocky Mountains to the Pacific Coast and from Baja Mexico to southeast Alaska and the Yukon Territory at elevations up to 3,640 m (11,940 ft) (Stebbins 2003, Hammerson 1999). One subspecies, the Boreal Toad (Anaxyrus boreas boreas), is currently recognized as occurring in Montana. However, mitochondrial DNA analysis indicates that four main phylogenetic groups exist, and each may warrant recognition as separate species: (1) a southern Rocky Mountain group in Colorado and southern Wyoming; (2) a southern Utah group; (3) a northwest group including all specimens in Montana, northern Idaho, and northern Wyoming; and (4) a southwest group composed of individuals currently recognized as the California Toad (Anaxyrus boreas halophilus), the Black Toad (Anaxyrus exsul), and the Amargosa Toad, (Anaxyrus nelson) (Goebel 1996). If these phylogenetic groups are eventually recognized as full species it is likely that populations across Montana and the Pacific Northwest will be recognized as the Western Toad, (Anaxyrus boreas). In Montana the species has been documented across the mountainous portion of the state west of the Beartooth Plateau, and the eastern edge of the Castle, Little Belt, and Highwood Mountains (Black 1970b, Black 1971).
Maximum elevation: 2,810 m (9,220 ft) in Gallatin County (Maxell et al. 2003).
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
No information is available specific to Montana. Elsewhere it is known that the Western Toad migrates between aquatic breeding and terrestrial nonbreeding habitats. In Colorado, movements of 900 meters (with 95 meters change in elevation) to 4 kilometers have been reported (Hammerson 1999), and radio-tracked females in Idaho have been observed to move up to 2.4 kilometers from breeding ponds (Koch and Peterson 1995). Movement patterns are highly variable, with some individuals remaining in the same location for several days, then moving 50 meters or more on several consecutive nights.
The Western Toad is known to utilize a wide variety of habitats, including desert springs and streams, meadows and woodlands, mountain wetlands, beaver ponds, marshes, ditches, and backwater channels of rivers where they prefer shallow areas with mud bottoms (Brunson 1952, Carpenter 1953, Black 1970b, Campbell 1970c, Nussbaum et al. 1983, Baxter and Stone 1985, Russell and Bauer 1993, Koch and Peterson 1995, Cavallo 1997, Hart et al. 1998, Hammerson 1999). Forest cover around occupied montane wetlands may include Aspen (Populus tremuloides
), Douglas-fir (Pseudotsuga menziesii
), Lodgepole Pine (Pinus contorta
), Engelmann Spruce (Picea engelmannii
), and Subalpine Fir (Abies lasiocarpa
); in local situations it may also be found in Ponderosa Pine (Pinus ponderosa
) forest. They also occur in urban settings, sometimes congregating under streetlights at night to feed on insects (Hammerson 1999). Normally they remain close to ponds, lakes, reservoirs, and slow-moving rivers and streams during the day, but may range widely at night.
Habitats used by Western Toads in Montana are similar to those reported for other regions, and include low elevation beaver ponds, reservoirs, streams, marshes, lake shores, potholes, wet meadows, and marshes, to high elevation ponds, fens, and tarns at or near the treeline (Rodgers and Jellison 1942, Brunson and Demaree 1951, Miller 1978, Marnell 1997, Werner et al. 1998a, Boundy 2001). Forest cover in or near encounter sites is often unreported, but Western Toads have been noted in open-canopy Ponderosa Pine woodlands and closed-canopy dry conifer forest in Sanders County (Boundy 2001), Willow (Salix
spp.) wetland thickets and Aspen stands bordering Engelmann Spruce stands in Beaverhead County (Jean et al. 2002), and mixed Ponderosa Pine/Cottonwood/Willow sites or Douglas-fir/Ponderosa Pine forest in Ravalli and Missoula counties (Paul Hendricks, personal observation).
Ecological Systems Associated with this Species
- Details on Creation and Suggested Uses and Limitations
How Associations Were Made
We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for
vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
- Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
- Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
- Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.
In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.
However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if
point observations were associated with that system.
Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.
The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.
If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.
Suggested Uses and Limitations
Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.
These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: mtnhp.org/requests
) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.
Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.
Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.
Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).
Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
- Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
- Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
- Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.
- Commonly Associated with these Ecological Systems
Forest and Woodland Systems
Human Land Use
Recently Disturbed or Modified
Shrubland, Steppe and Savanna Systems
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Forest and Woodland Systems
Human Land Use
Recently Disturbed or Modified
Shrubland, Steppe and Savanna Systems
Adults feed on a variety of invertebrates including spiders, daddy longlegs, and millipeds, but rely most heavily on ground dwelling coleopterans and hymenopterans. They are also known to eat smaller vertebrates including smaller individuals of their own species (Cunningham 1954, Moore and Strickland 1955, Mullally 1958, Livezey 1961, Campbell 1970a, Miller 1975, 1978, Hansen and Thomason 1991).
Research outside the state shows that metamorphosed individuals feed on various small invertebrates, including seven orders of flying insects, spiders, mites, daddy longlegs, snails, crayfish, sowbugs (terrestrial amphipods), and earthworms (Nussbaum et al. 1983, Hammerson 1999). Larvae filter suspended plant material or feed on bottom detritusand other dead tadpoles or adults (Black 1970d; Franz 1971; Loeffler 1998).
Eggs and larvae develop in still, shallow areas of ponds, lakes, or reservoirs or in pools of slow-moving streams, often where there is sparse emergent vegetation. Basking groups of up to 1000 young-of-year have been observed in Waterton National Park; basking sites may be important at high elevations (Black and Black 1969). They are active day/evening in early summer and late evening/night when it's hot (e.g. August) (Miller 1975).
Adults and juveniles apparently use olfactory and celestial cues, respectively, to orient (Tracy and Dole 1969a; Tracy 1971). The active period typically begins in April or May and extends to September or October, depending on elevation and latitude (Russell and Bauer 1993, Koch and Peterson 1995, Hammerson 1999), although adults may be active in January and February in coastal populations (Nussbaum et al. 1983). In Montana, records extend from late April to early October (Rodgers and Jellison 1942, Brunson and Demaree 1951, Black and Brunson 1971, Hendricks and Reichel 1996a, Boundy 2001). Smaller juveniles are active almost exclusively diurnally and adults are usually active at night except during the spring and at high elevation (Mullally 1958, Lillywhite et al. 1973, Sullivan 1996, Sullivan et al. 1996, Maxell 2000). Adults may move more than 800 m in a night, may move more than 4 km away from water after breeding, and can remain away from surface water for relatively long periods of time (Pimentel 1955, Tracy and Dole 1969, Campbell 1970b, Loeffler 1998). Juveniles may disperse up to or more than 4 km from their natal site (Sornborger 1979). Adult and juvenile toads are freeze intolerant and overwinter and shelter in underground caverns, or more commonly in rodent burrows (Mullally 1952, Black 1970d, Nussbaum et al. 1983, Smits 1984, Koch and Peterson 1995, Hammerson 1999, Jones 1999).
Predators of adult Western Toads include Raccoon (Procyon lotor
), domestic dog, Coyote (Canis latrans
), Red Fox (Vulpes vulpes
), Short-tailed Weasel (Mustela erminea
), American Mink (Mustela vison
), Marten (Martes americana
), Badger (Taxidea taxus
), American Black Bear (Ursus americanus
), Northern Pygmy-Owl (Glaucidium gnoma
), Black-billed Magpie (Pica hudsonia
), Common Raven (Corvus corax
), American Crow (Corvus brachyrhynchos
), Steller's Jay (Cyancitta stelleri
), Canada Jay (Perisoreus canadensis
), American Robin (Turdus migratorius
), Loggerhead Shrike (Lanius ludovicianus
), and Northern Shrike (Lanius borealis
) (Salt 1979, Corn 1993, Olson 1989, Brothers 1994, Koch and Peterson 1995, Hammerson 1999, Jones et al. 1999). Predators of Western Toad tadpoles include Mallard (Anas platyrhynchos
), Spotted Sandpiper (Actitis macularius
), Terrestrial Gartersnake (Thamnophis elegans
), Tiger Salamander (Ambystoma mavortium
), Wood Frog (Lithobates sylvaticus
) tadpoles and diving beetle larvae. Predators of Western Toad in Montana are not documented.
The reproductive biology of Western Toads in Montana is poorly described. The known breeding period extends from April to mid-July. Breeding aggregations of more than 40 adult males have been reported in mid-May (Black and Brunson 1971). Timing of breeding is dependent on temperature, snowmelt, and/or the presence of surface water from flooding and takes place from May to July in shallow areas of large and small lakes, beaver ponds, temporary ponds, slow-moving streams, and backwater channels of rivers (Metter 1961, Black 1970b). Water chemistry at most breeding sites generally has a high pH (>8.0), high conductivity, and high acid-neutralizing capacity (Koch and Peterson 1995).
Females wrap egg strings around emergent vegetation or clumped loosely in shallow (usually less than 15 cm) waters (Black 1970b; Hammerson 1999). Eggs are laid in two jelly strings from early May to late June and hatch in approximately 5 days. Tadpoles commonly form dense aggregations in shallow warmer waters from late May to early September. Tadpoles metamorphose en masse in 40 (Maxell et al. 2009) to 75 (Loeffler 1998) days and metamorphs can be found in dense aggregations adjacent to breeding grounds (Turner 1952a, Black and Black 1969, Lillywhite and Wassersug 1974, Devito et al 1998). Recently metamorphosed toadlets have been reported from early June to late August (Brunson and Demaree 1951, Werner and Reichel 1994, Reichel 1995, Hendricks and Reichel 1996a, Marnell 1997, Boundy 2001, Burton et al. 2002). Size of one clutch in the Bitterroot Valley of Ravalli County was 20,000 eggs. These eggs were laid in late May and produced metamorphosed toadlets by July 11, about 40 to 49 days after oviposition (Maxell et al. 2002).
In other areas of the species' range, the breeding period is known to be variable depending on location. In the mountains, breeding follows the melt of winter snowpack, and in some cases, eggs may be laid when ponds are still rimmed with ice. Water temperature may be as low as 7.5 °C but usually more than 9.0 °C (Salt 1979). At a given site, breeding may extend over several weeks, although a peak usually occurs.
Breeding aggregations may be quite large (more than 2,000 adults), but most often are much smaller, with males outnumbering females. Typical clutches in Colorado contain 3,000 to 9,000 eggs (mean of 5,200 eggs), although in the Pacific Northwest clutches of 12,000 eggs are considered normal, and may reach 16,000 eggs (Nussbaum et al. 1983, Koch and Peterson 1995, Hammerson 1999). Eggs hatch in 3 to 12 days. Tadpoles are about 1.0 cm total length at hatching and grow to about 2.5 to 3.0 cm. They sometimes are found in huge aggregations; one in Yellowstone National Park, Wyoming measured 0.5 m wide and more than 36 m long, and another in the Oregon Cascades was 1.0 m wide by 300 m long (Nussbaum et al. 1983, Koch and Peterson 1995).
Tadpoles metamorphose in the first summer. They can take two months or more to reach metamorphosis, depending on the water temperature. At high elevation sites near the treeline in Wyoming and Colorado, tadpoles may fail to metamorphose (Baxter and Stone 1985, Hammerson 1999). Persistence of these populations may be dependent on immigration of juveniles and adults from lower elevations as there are no observations of tadpoles overwintering. Metamorphosis usually occurs during August in Colorado and Oregon but may occur in late July to mid-September. Toadlets may overwinter along the borders of the pools where they developed or move to other nearby wetlands. The minimum age of breeding males is four years, and six years for breeding females; captive animals have lived up to 35 years (Russell and Bauer 1993, Hammerson 1999).
The following was taken from the Status and Conservation section for the Western Toad account in Maxell et al. 2009
Within the last twenty-five years populations of Western Toad have undergone population crashes
in Colorado, Utah, southeast Wyoming, and New Mexico (Stuart and Painter 1994, Ross et al. 1995, Corn et al. 1997, Loeffler 1998). (Anaxyrus boreas
) is now listed as endangered by the State of Colorado and considered a candidate species which is warranted, but precluded, for federal listing by the USFWS in the southern Rocky Mountains (Colorado, southeast Wyoming and northern New Mexico) (Ross et al. 1995, Loeffler 1998). The estimated cost of implementing the first four years of the recovery plan for the Southern Rocky Mountain population is one million twenty-five thousand dollars (Loeffler 1998). Reports of declines in Western Toad populations have also been reported in Oregon and California (Blaustein et al. 1994a, Stebbins and Cohen 1995, Drost and Fellers 1996, Fisher and Shaffer 1996).
Until the late 1990’s many biologists believed that populations in the northern Rocky Mountains had not undergone similar declines. However, surveys in the late 1990’s revealed that populations of the Western Toad were absent from a large number of their historic localities and that although they were still widespread across the landscape they occupied an extremely small proportion of suitable habitat (less than 10% in most cases, but usually less than 5%) (Werner and Reichel 1994, 1996a, Reichel 1995, 1996, 1997b, Koch and Peterson 1995, Koch et al. 1996, Hendricks and Reichel 1996a, Werner et al. 1998a, reviewed by Maxell et al. 1998). As a result of these findings the USFS listed the Western Toad as a sensitive species in all Region 1 Forests (USDAFS 1999) and initiated a regional inventory program in Montana. The systematic inventory of standing water bodies in 40 randomly chosen 6th level Hydrologic Unit Code (HUC) watersheds across western Montana during the summer of 2000 also found Western Toad populations to be widespread, but extremely rare. Of the 40 watersheds that were surveyed Western Toads were found in 11 (27%), and of the 33 watersheds that contained suitable breeding habitat they were found breeding (eggs, larvae, or metamorphs observed) in 7 (21%). However, of the 347 standing water bodies that were surveyed within these watersheds, Western Toads were only found at 13 (3.7%) and were found breeding at only 9 (2.6%). Furthermore, at sites where Western Toads were observed, only small numbers of adults or relatively small numbers of eggs or larvae were observed. Similarly, in an inventory of approximately 400 standing water bodies in Glacier National Park during the summers of 1999 and 2000, Western Toads were found and bred at approximately 5% (Steve Corn, USGS BRD Aldo Leopold Institute, pers. comm.). Similar patterns have been observed on the Flathead Indian Reservation where years have been skipped between breeding events (Kirwin Werner, Salish Kootenai College, pers. comm.). Thus, the evidence to date suggests that Western Toads have either undergone a decline in the 1980s and are now in the process of recovering, or they have undergone a decline and are continuing to decline because populations are small, isolated, and/or subject to one or more factors that are impacting populations separately or synergistically.
Risk factors relevant to the viability of populations of this species are likely to include all the risk factors described above. As a supplement to this information managers may wish to refer to Loeffler (1998) who, for the recovery of Western Toad populations in the Southern Rocky Mountains, reviews these and other general risk factors and provides management guidelines to mitigate their impacts. Individual studies that specifically identify risk factors or other issues relevant to the conservation of Western Toads include the following. (1) Carey (1993) observed the disappearance of several populations of Western Toads in the West Elk Mountains of Colorado between 1974 and 1982 and during this period found many Western Toads with symptoms of red-leg disease, a common bacterial infection in amphibians and fish. She hypothesized that an unidentified environmental factor had caused sublethal stress of the Western Toads, which caused immune response to be suppressed leading to the systemic infection and death of Western Toads. More recently the chytrid fungus (Batrachochytrium dendrobatidis
), which is suspected to be responsible for declines of amphibians in Australia, Central America, and the western United States has been found to have caused mass mortalities in Western Toad populations in Colorado during the summer of 1999 (Berger et al. 1998, Daszak et al. 1999, 2000, Morell 1999, Milius 1999, 2000, Carey et al. 2000). As was observed for declines in the late 1970’s and early 1980’s only metamorphosed individuals died (Carey et al. 2000). The fungus only seems to attack keratinized tissues, so metamorphosed individuals with lots of keratinized tissues die and tadpoles with keratinized tissues only around the mouthparts survive until metamorphosis (Berger et al. 1998, Morell 1999). Another line of evidence to suggest that the chytrid fungus was responsible for declines in the late 1970’s and early 1980’s is that Northern Leopard Frog (Lithobates pipiens
) populations in Colorado crashed at the same time that Western Toad populations did and museum specimens of Northern Leopard Frogs that were collected during these time periods have now been found to have the chytrid fungus (Daszak et al. 1999, Milius 2000). Thus, the chytrid fungus may be the most likely cause of declines of Western Toads and the near extirpation of Northern Leopard Frogs in western Montana in the late 1970’s and early 1980’s and clearly represents a threat to populations today. Another fungus, Saprolegnia ferax
, has been found to cause 95% mortality of an estimated 2,496,000 Western Toad embryos at a site in Oregon (Blaustein et al. 1994c). Spread of the fungus between egg strings is enhanced by the behavior of Western Toads because females often deposit eggs communally (Kiesecker and Blaustein 1997a). (2) Hailman (1984) found that Western Toads tended to congregate around roads in the late evening and early morning. Cunningham (1954) found hundreds of Western Toads flattened on a highway the morning following a summer thunderstorm. (3) Olson (1989, 1992a) reports that Common Ravens killed large number of breeding Western Toads (20% of the entire breeding population at one site) at three sites in the Oregon Cascades. The author speculates that human activity near these sites may serve to concentrate Common Raven activity in the area and subsequently leads to Western Toad predation. Similarly, Brothers (1994) found Western Toads being preyed on by American Crows and Beiswenger (1981) found tadpoles being preyed upon by Canada Jays. Furthermore, Jones et al. (1999) report predation of Western Toad tadpoles, metamorphs, and adults by a number of avian and mammalian species that may be attracted to areas of human activity and/or subsidized by the presence of humans, subsequently leading to increased rates of predation. These animals included Mallards, Spotted Sandpipers, American Robins, Red Fox, Raccoon, and a domestic dog. Sherman and Morton (1993) also report high levels of predation on breeding aggregations of the closely related Yosemite Toad (Anaxyrus canorus
) by Clark’s Nutcrackers (Nucifraga columbiana
), California Gulls (Larus californicus
), and Common Ravens. Fisher and Shaffer (1996) implicate introduced American Bullfrog (Lithobates catesbeianus
) and fish predators in the decline of Western Toads in the Sacramento and San Joaquin Valleys in California. However, Jones et al. (1999) found that neither Cutthroat Trout (Oncorhynchus
sp.) or Brook Trout (Salvelinus fontinalis
) would prey on tadpoles and Licht (1968) found that Western Toad eggs were not palatable to fish. Furthermore, both Drost and Fellers (1996) and Corn et al. (1997) found Western Toads breeding at sites with and without fish. (4) After what may have been the first successful reproductive event at a site in southeastern Idaho in 10 years Bartelt (1998a) documented the deaths of thousands of Western Toad metamorphs when 500-1,000 sheep were herded through the drying pond the toadlets were concentrated. He found that hundreds of animals had been directly killed underfoot and hundreds more died soon afterward as a result of desiccation because the vegetation they had been hiding in had been trampled to the point that it no longer provided a moist microhabitat. (5) Antimycin and rotenone, two commonly used piscicides, are both toxic to Western Toad tadpoles (Loeffler 1998). (6) Johnson and Prine (1976) exposed juvenile Western Toads to the insecticides Abate, fenthion, chlorpyrifos-methyl, chlorpyrifos-ethyl, methylparathion, and the insect growth regulator Altosid for 24 hours at one half the concentrations usually applied in the field. They found that Western Toads exposed to the insecticides reduced their activity levels and had lower tolerance to high temperatures than Western Toads in the control group. (7) Porter and Hakanson (1976) found that a variety of heavy metals found in drainage water from mines in Colorado were highly lethal to Western Toad larvae. Furthermore, they found that lethal pH for tadpoles ranges from 3.1 to 4.0. Other studies report that no significant embryo mortality is observed for Western Toads until pH falls below 4.9, but embryos have an LC50 at pH less than or equal to 4.5 (Corn et al. 1989, Corn and Vertucci 1992, Vertucci and Corn 1996). (8) In Oregon, Blaustein et al. (1994d) found that survival rates for Western Toad embryos was lower when they were exposed to ambient UV-B radiation than when they were shielded from UV-B radiation and attributed this to the presence of low levels of photolyase, an enzyme that is known to repair UVB damage to DNA. However, Kiesecker and Blaustein (1995) found that UV-B may only be impacting embryo survival as a result of a synergistic interaction with the fungus Saprolegnia ferax
. They found that embryos had 95-100% survival rates when exposed to ambient UV-B radiation in the absence of Saprolegnia
. However, when embryos were infected with Saprolegnia
survival dropped to 50% at ambient UV-B levels. Similarly, Corn (1998) failed to find a relationship between exposure to UV-B and embryo survival to hatching in Colorado and noted that a number of other studies have also failed to find a convincing impact of ambient levels of UV-B radiation on amphibian embryos. At artificially high levels of UV-B exposure Worrest and Kimeldorf (1975) report a decline in larval survivorship of Western Toads from 94-100% in controls to 0%, 17%, and 41% for UV-B treatments exposed to 0, 2, and 4 hours of photoreactivating (>315 nm) light following UV-B exposure.
- Literature Cited AboveLegend: View Online Publication
- [USDAFS] USDA Forest Service. 1999. Update of U.S. Forest Service Northern Region Sensitive Species List. 12 March, 1999. Region 1 U.S. Forest Service Supervisors Office, Missoula, Mt. 20 P.
- Baxter, G.T. and M.D. Stone. 1985. Amphibians and reptiles of Wyoming. Second edition. Wyoming Game and Fish Department. Cheyenne, WY. 137 p.
- Beiswenger, R.E. 1981. Predation by gray jays on aggregating tadpoles of the boreal toad (Bufo boreas). Copeia 1981(2): 459-460.
- Berger, L., R. Speare, P. Daszak, D.E. Green, A.A. Cunningham, C.L. Goggin, R. Slocombe, M.A. Ragan, A.D. Hyatt, K.R. McDonald, H.B. Hines, K.R. Lips, G. Marantelli and H. Parkes. 1998. Chytridiomycosis causes amphibian mortality associated with population declines in the rain forests of Australia and Central America. Proceedings of the National Academy of Sciences 95: 9031-9036.
- Black, J. H. and R. B. Brunson. 1971. Breeding behavior of the boreal toad (Bufo boreas boreas) (Baird and Girard) in western Montana. Great Basin Naturalist 31: 109-113.
- Black, J.H. 1971. The toad genus Bufo in Montana. Northwest Science 45: 156-162.
- Black, J.H. and J.N. Black. 1969. Postmetamorphic basking aggregations of the boreal toad (Bufo boreas boreas). Canadian Field Naturalist 83: 155-156.
- Blaustein, A.R., D.B. Wake, and W.P. Sousa. 1994a. Amphibian declines: Judging stability, persistence, and susceptibility of populations to local and global extinctions. Conservation Biology 8(1):60-71.
- Blaustein, A.R., D.G. Hokit, R.K. O'Hara, and R.A. Holt. 1994c. Pathogenic fungus contributes to amphibian losses in the Pacific Northwest. Biological Conservation 67: 251-254.
- Blaustein, A.R., P.D. Hoffman, D.G. Hokit, J.M. Kiesecker, S.C. Walls, and J.B. Hays. 1994d. UV repair and resistance to solar UV-B in amphibian eggs: a link to population declines? Proceedings of the National Academy of Sciences 91: 1791-1795.
- Boundy, J. 2001. Herpetofaunal surveys in the Clark Fork Valley region, Montana. Herpetological Natural History 8: 15-26.
- Bragg, A.N. 1937a. A note on the metamorphosis of the tadpoles of Bufo cognatus. Copeia 1937: 227-228.
- Brothers, D. R. 1994. Bufo boreas (western toad) predation. Herpetological Review 25(3): 117.
- Brunson, R. B. 1952. Recent collections of Bufo boreas from western Montana. Proceedings of Montana Academy of Sciences 11: 17-19.
- Brunson, R.B. and H.A. Demaree, Jr. 1951. The herpetology of the Mission Mountains, Montana. Copeia (4):306-308.
- Burton, S.R., D.A. Patla, and C.R. Peterson. 2002. Amphibians of Red Rock Lakes National Wildlife Refuge: occurrence, distribution, relative abundance, and habitat associations. Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 66 p.
- Campbell, J.B. 1970a. Food habits of the boreal toad (Bufo boreas boreas) in the Colorado front range. Journal of Herpetology 14 or 4: 83-85.
- Campbell, J.B. 1970b. Hibernacula of a population of Bufo boreas boreas in the Colorado Front Range. Herpetologica 26: 278-282.
- Campbell, J.B. 1970c. Life history of Bufo boreas boreas in the Colorado Front Range. Ph.D. Dissertation, University of Colorado, Boulder. 110pp.
- Carey, C. 1993. Hypothesis concerning the causes of the disapperance of the boreal toads from the mountains of Colorado. Conservation Biology 7(2): 355-360.
- Carey, C., P.S. Corn, M.S. Jones, L.J. Livo, E. Muths, and C.W. Loeffler. 2000. Environmental and life history factors that limit recovery in southern Rocky Mountain populations of boreal toads (Bufo boreas boreas). In: Status and Conservation of Unite
- Cavallo, B.J. 1997. Floodplain habitat heterogeneity and the distribution, abundance, and behavior of fishes and amphibians in the Middle Fork Flathead River Basin, Montana. M.S. Thesis. University of Montana, Missoula, MT. 133 p.
- Corn, P.S. 1993. Bufo boreas (boreal toad): predation. Herpetological Review 24(2): 57.
- Corn, P.S. 1998. Effects of ultraviolet radiation on boreal toads in Colorado. Ecological Applications 8(1): 18-26.
- Corn, P.S. and F.A. Vertucci. 1992. Descriptive risk assessment of the effects of acid deposition on Rocky Mountain Amphibians. Journal of Herpetology 26(4): 361-369.
- Corn, P.S., M.L. Jennings, and E. Muths. 1997. Survey and assessment of amphibian populations in Rocky Mountain National Park. Northwest. Nat. 78:34-55.
- Corn, P.S., W. Stolzenburg, and B.R. Bury. 1989. Acid precipitation studies in Colorado and Wyoming: interim report of surveys of montane amphibians and water chemistry. U.S. Fish and Wildlife Service Biological Report 89(40.26). Air Pollution and Acid Rain Report Number 26. 56 p.
- Cunningham, J.D. 1954. A case of cannabilism in the toad Bufo boreas halophilus. Herpetologica 10: 166.
- Daszak, P., A.A. Cunningham and A.D. Hyatt. 2000. Emerging infectious diseases of wildlife - threats to biodiversity and human health. Science 287: 443-449.
- Daszak, P., L. Berger, A.A. Cunningham, A.D. Hyatt, D.E. Green, and R. Speare. 1999. Emerging infectious diseases and amphibian population declines. Emerging Infectious Diseases 5(6): 735-748.
- Devito, J., D.P. Chivers, J.M. Kiesecker, A. Marco, E.L. Wildy, and A.R. Blaustein. 1998. The effects of snake predation on metamorphosis of western toads (Bufo boreas) (Amphibia, Bufonidae). Ethology 104: 185-193.
- Drost, C.A. and G.M. Fellers. 1996. Collapse of a regional frog fauna in the Yosemite area of the California Sierra Nevada, USA. Conservation Biology 10 (2): 414-425.
- Fisher, R.N. and H.B. Shaffer. 1996. The decline of amphibians in California's Great Central Valley. Conservation Biology 10(5): 1387-1397.
- Franz, R. 1971. Notes on the distribution and ecology of the herpetofauna of northwestern Montana. Bulletin of the Maryland Herpetological Society 7: 1-10.
- Goebel, A.M. 1996. Systematics and conservation of bufonids in North America and in the Bufo boreas species group. Ph.D. Dissertation. University of Colorado, Boulder, CO. 274 p.
- Hailman, J.P. 1984. Bimodal nocturnal activity of the western toad (Bufo boreas) in relation to ambient light. Copeia 1984(2): 283-290.
- Hammerson, G.A. 1999. Amphibians and reptiles in Colorado. University Press of Colorado & Colorado Division of Wildlife. Denver, CO. 484 p.
- Hansen, R.W. and B. Thomason. 1991. Contia tenuis (sharptail snake). Predation. Herpetological Review 22(2): 60-61.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, The University of Montana. Missoula, MT. vii + 1302 pp.
- Hendricks, P. and J.D. Reichel. 1996a. Amphibian and reptile survey of the Bitterroot National Forest: 1995. Montana Natural Heritage Program. Helena, MT. 95 p.
- Jean, C., P. Hendricks, M. Jones, S. Cooper, and J. Carlson. 2002. Ecological communities on the Red Rock Lakes National Wildlife Refuge: inventory and review of aspen and wetland systems. Report to Red Rock Lakes National Wildlife Refuge.
- Johnson, C.R. and J.E. Prine. 1976. The effects of sublethal concentrations of organophosphorus insecticides and an insect growth regulator on temperature tolerance in hydrated and dehydrated juvenile western toads, Bufo boreas. Comparative Biochemistry and Physiology 53A :147-149.
- Jones, M.S. (ed.). 1999. Boreal toad research progress report: 1998. Colorado Division of Wildlife, Ft. Collins, CO. 118 p.
- Jones, M.S., J.P. Goettl, and L.J. Livo. 1999. Bufo boreas (boreal toad): predation. Herpetological Review 30:91.
- Karlstrom, E.L. 1962a. The toad genus Bufo in the Sierra Nevada of California; ecological and systematic relationships. Ph.D. Dissertation, University of California Berkeley. 95 pp.
- Kiesecker, J.M. and A.R. Blaustein. 1995. Synergism between UV-B radiation and a pathogen magnifies amphibian embryo mortality in nature. Proceedings of the National Academy of Sciences 92: 11049-11052.
- Kiesecker, J.M. and A.R. Blaustein. 1997b. Influences of egg laying behavior on pathogenic infection of amphibian eggs. Conservation Biology 11(1): 214-220.
- Koch, E.D. and C.R. Peterson. 1995. Amphibians and reptiles of Yellowstone and Grand Teton national parks. University of Utah Press, Salt Lake City, UT. 188 p.
- Koch, E.D., G. Williams, C.R. Peterson and P.S. Corn. 1996. Conference on declining and sensitive amphibians in the Northern Rockies and the Pacific Northwest: a summary paper. Idaho Herpetological Society Technical Bulletin and U.S. Fish and Wildlife Service Report, Boise, Idaho.
- Licht, L.E. 1969b. Palatability of Rana and Hyla eggs. American Midland Naturalist 82: 296-298.
- Lillywhite, H.B., and R.J. Wassersug. 1974. Comments on a postmetamorphic aggregation of Bufo boreas. Copeia 1974(4): 984-986.
- Lillywhite, H.B., P. Licht, and P. Chelgren. 1973. The role of behavioral thermoregulation in the growth energetics of the toad Bufo boreas. Ecology 54: 374-383.
- Livezey, R.L. 1961. Food of adult and juvenile Bufo boreas exsul. Herpetologica 17(4): 267-268.
- Livezey, R.L. and A.H. Wright. 1947. A synoptic key to salientian eggs of the United States. American Midland Naturalist 37: 179-222.
- Loeffler, C. (ed.). 1998. Conservation plan and agreement for the management and recovery of the Southern Rocky Mountain population of the boreal toad (Bufo boreas boreas). Boreal Toad Recovery Team. 80 pp.
- Marnell, L. E. 1997. Herpetofauna of Glacier National Park. Northwestern Naturalist 78:17-33.
- Maxell, B. A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to USFS Region 1, Order Number 43-0343-0-0224. University of Montana, Wildlife Biology Program. Missoula, MT. 161 p.
- Maxell, B.A., J.K. Werner, P. Hendricks, and D.L. Flath. 2003. Herpetology in Montana: a history, status summary, checklists, dichotomous keys, accounts for native, potentially native, and exotic species, and indexed bibliography. Society for Northwestern Vertebrate Biology, Northwest Fauna Number 5. Olympia, WA. 135 p.
- Maxell, B.A., K.J. Nelson, and S. Browder. 2002. Record clutch size and observations on breeding and development of the western toad (Bufo boreas) in Montana. Northwestern Naturalist 83(1):27-30.
- Maxell, B.A., P. Hendricks, M.T. Gates, and S. Lenard. 2009. Montana amphibian and reptile status assessment, literature review, and conservation plan, June 2009. Montana Natural Heritage Program. Helena, MT. 643 p.
- Maxwell, B.A., P.S. Corn, P. Hendricks, T. Koch, C. Peterson, and K. Werner. 1998. Brief overview of boreal toad status in USFS Region 1. U.S. Forest Service, Missoula, Montana. 8 p.
- Metter, D.E. 1961. Water levels as an environmental factor in breeding season of Bufo boreas boreas. Copeia 1961(4): 488.
- Milius, S. 1999. Killer skin fungus nails boreal toads. Science News 156: 219.
- Milius, S. 2000. New frog-killing disease may not be so new. Science News 157: 133.
- Miller, J. D. 1975. Interspecific food relationships of anurans in northwestern Montana and fluoride accumulation in amphibians and reptiles in northwestern Montana. M.S. thesis. University of Montana, Missoula, MT. 105 p.
- Miller, J.D. 1978. Observations on the diets of Rana pretiosa, Rana pipiens, and Bufo boreas from western Montana. Northwest Science 52(3): 243-249.
- Moore, J.E. and E.H. Strickland. 1955. Further notes on the food of Alberta amphibians. American Midland Naturalist 52: 221-224.
- Morell, V. 1999. Are pathogens felling frogs? Science 284: 728-731.
- Mullally, D.P. 1952. Habits and minimum temperatures of the toad Bufo boreas halophilus. Copeia 1952(4): 274-276.
- Mullally, D.P. 1958. Daily period of activity of the western toad. Herpetologica 14: 29-31.
- Nussbaum, R.A., E.D. Brodie, Jr. and R.M. Storm. 1983. Amphibians and reptiles of the Pacific Northwest. University of Idaho Press. Moscow, ID. 332 pp.
- Olson, D. H. 1988. The ecological and behavioral dynamics of breeding in three sympatric anuran amphibians. Ph.D. dissertation. Department of Zoology, Oregon State University, Corvallis, Oregon. 260 p.
- Olson, D.H. 1989. Predation on breeding western toads (Bufo boreas). Copeia (2):391-397.
- Pimentel, R.A. 1955. Habitat distribution and movements of Bufo b. boreas, Baird and Girard. Herpetologica 11: 72.
- Porter, K.R. and D.E. Hakanson. 1976. Toxicity of mine drainage to embyonic and larval boreal toads (Bufonidae: Bufo boreas). Copeia 1976(2): 327-331.
- Reichel, J.D. 1996. Preliminary amphibian and reptile survey of the Helena National Forest: 1995. Montana Natural Heritage Program. Helena, MT. 87 pp.
- Reichel, J.D. 1997b. Animal species of special concern in Montana. Montana Natural Heritage Program. Helena, MT. 9 p.
- Reichel, J.D. 1995a. Preliminary amphibian and reptile survey of the Lewis & Clark National Forest: 1994. Montana Natural Heritage Program. Helena, MT. 92 p.
- Rodgers, T. L. and W. L. Jellison. 1942. A collection of amphibians and reptiles from western Montana. Copeia (1):10-13.
- Ross, D.A., T.C. Esque, R.A. Fridell, and P. Hovingh. 1995. Historical distribution, current status, and a range extension of Bufo boreas in Utah. Herpetological Review 26(4): 187-189.
- Russell, A. P. and A. M. Bauer. 1993. The amphibians and reptiles of Alberta. University of Calgary Press. Calgary, Alberta. 264 p.
- Salt, J.R. 1979. Some elements of amphibian distribution and biology in the Alberta Rockies. Alberta Naturalist 9(3): 125-136.
- Samollow, P.B. 1980. Selective mortality and reproduction in a natural population of Bufo boreas. Evolution 34(1): 18-39.
- Sherman, C.K. and M.L. Morton. 1993. Population declines of Yosemite Toads in the Eastern Sierra Nevada of California. Journal of Herpetology 27(2): 186-198.
- Smits, A.W. 1984. Activity patterns and thermal biology of the toad Bufo boreas halophilus. Copeia 198493): 689-696.
- Sornborger, M.B. 1979. Population dynamics of the western toad, Bufo boreas halophilus, at Hidden Lake, Mt. San Jacinto State Park. Masters Thesis, California State Polytechnic University, Pomona, California. 77 pp.
- Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. 3rd Edition. Houghton Mifflin Company, Boston and New York. 533 p.
- Stebbins, R.C. and N.W. Cohen. 1995. A natural history of amphibians. Princeton University Press. Princeton, NJ. 316 pp.
- Stuart, J.N. and C.W. Painter. 1994. A review of the distribution and status of the boreal toad (Bufo boreas boreas) in New Mexico. Bulletin of the Chicago Herpetological Society 29 (6) :113-116.
- Sullivan, S.R. 1996. Daily activity patterns of western toads (Bufo boreas) on the Targhee National Forest, Idaho. Honors Thesis, Carroll College, Helena, Montana.
- Sullivan, S.R., P. Bartelt and C. Peterson. 1996. Daily activity patterns of Western toads on the Targhee National Forest, Idaho. Intermountain Journal of Sciences 2(2): 61-62.
- Tracy, C.R. 1971. Evidence for the use of celestial cues by dispersing immature California toads (Bufo boreas). Copeia 1971(1): 145-147.
- Tracy, C.R. and J.W. Dole. 1969a. Evidence of celestial orientation by California toads (Bufo boreas) during breeding migration. Bulletin of Southern California Academy of Science 68(1): 10-18.
- Turner, F.B. 1952a. Peculiar aggregations of toadlets on Alum Creek. Yellowstone Nature Notes 26(5): 57-58.
- Vertucci, F.A. and P.S. Corn. 1996. Evaluation of episodic acidification and amphibian declines in the Rocky Mountains. Ecological Applications 6(2): 449-457.
- Werner, J.K. and J.D. Reichel. 1996. Amphibian and reptile monitoring/survey of the Kootenai National Forest: 1995. Montana Natural Heritage Program. Helena, MT. 115 pp.
- Werner, J.K. and J.D. Reichel. 1994. Amphibian and reptile survey of the Kootenai National Forest: 1994. Montana Natural Heritage Program. Helena, MT. 104 p.
- Werner, J.K., T. Plummer, and J. Weaslehead. 1998a. Amphibians and reptiles of the Flathead Indian Reservation. Intermountain Journal of Sciences 4(1-2): 33-49.
- Worrest, R.C. and D.J. Kimeldorf. 1975. Photoreactivation of potentially lethal, UV-induced damage to boreal toad (Bufo boreas boreas) tadpoles. Life Science 17: 1545-1550.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- [PRESI] Powder River Eagle Studies Incorporated. 1998b. Spring Creek Mine 1997 wildlife monitoring studies. Powder River Eagle Studies Incorporated. Gillete, WY.
- [WWPC] Washington Water Power Company. 1995. 1994 wildlife report Noxon Rapids and Cabinet Gorge Reservoirs. Washington Water Power Company. Spokane, WA.
- Adams, M.J., B.R. Hossack, and R.A. Knapp. 2005. Distribution patterns of lentic-breeding amphibians in relation to ultraviolet radiation in western North America. Ecosystems 8(5):488-500.
- Adams, S.B., D.A. Schmetterling, and M.K. Young. 2005. Instream movements by boreal toads (Bufo boreas boreas). Herpetological Review 36(1):27-33.
- Aguirre, A. 1994. Declining toad populations. Conservation Biology 8(1): 7.
- Anderson, M.E. 1977. Aspects of the ecology of two sympatric species of Thamnophis and heavy metal accumulation with the species. M.S. thesis, University of Montana, Missoula. 147 pp.
- Annis, S.L., F.P. Dastoor, H. Ziel, P. Daszak, and J.E. Longcore. 2004. A DNA-based assay identifies Batrachochytrium dendrobatidis in amphibians. Journal of Wildlife Diseases 40(3):420-428.
- Atkinson, E.C. and M.L. Atkinson. 2003. Status of boreal toads on and adjacent to the Gallatin National Forest, Montana, with special reference to the Hebgen Lake and Bozeman Ranger Districts. Marmot's Edge Conservation. Report to the US Department of Agriculture. Forest Service, Bozeman, MT.
- Awbrey, F.T. 1972. "Mating call" of a Bufo boreas male. Copeia 1972(30: 579-581.
- Awbrey, F.T. 1972. "Mating call" of a Bufo boreas male. Copeia 1972(30: 579-581.
- Baldwin, R.A. 1974. The water balance response of the pelvic "patch" of Bufo punctatus and Bufo boreas. Comparative Biochemistry and Physiology A Comparative Physiology 47A: 1285-1295.
- Barrentine, C.D. 1991a. Food habits of western toads (Bufo boreas halophilus) foraging from a residential lawn. Herpetological Review 22(3) 1991: 84-87.
- Barrentine, C.D. 1991b. Survival of billbugs (Sphenophorus spp.) egested by western toads (Bufo boreas). Herpetological Review 22(1): 5.
- Bartelt, P.E. 1998a. Bufo boreas mortality. Herpetological Review 29(2): 96.
- Bartelt, P.E. 2000. A biophysical analysis of habitat selection in western toads (Bufo boreas) in southeastern Idaho. Dissertation, Idaho State University. 112 p.
- Bartelt, P.E. and C.R. Peterson. 1994. Riparian habitat utilization by western toads (Bufo boreas) and spotted frogs (Rana pretiosa) on the Targee National Forest. USDA Forest Service Contract # INT-93780-CCSA Final Report. 30 pp.
- Bartelt, P.E. and C.R. Peterson. 1995. Effects of grazing on movements and habitat use of western toads (Bufo boreas) on the Targhee National Forest. Idaho State University, Pocatello, Idaho. 15 pp.
- Bartelt, P.E. and C.R. Peterson. 2000. A description and evaluation of a plastic belt for attaching radio transmitters to western toads (Bufo boreas). Northwestern Naturalist 81: 122-128.
- Bartelt, P.E., C.R. Peterson, and R.W. Klaver. 2004. Sexual differences in the post-breeding movements and habitats selected by western toads (Bufo boreas) in southeastern Idaho. Herpetologica 60(4):455-467.
- Beal, M.D. 1951. The occurrence and seasonal activity of vertebrates in the Norris and Gibbon Geyser Basins of Yellowstone National Park. M.S. Thesis. Utah State Agricultural College. Logan, Utah. 61 pp.
- Beiswenger, R.E. 1978. Responses of Bufo tadpoles (Amphibian, Anura, Bufonidae) to laboratory gradients of temperature. Journal of Herpetology 12(4): 499-504.
- Belden, L.K., E.L. Wildy, and A.R. Blaustein. 2000b. Juvenile western toads, Bufo boreas, avoid chemical cues of snakes fed juvenile, but not larval, conspecifics. Animal Behaviour 59: 871-875.
- Benard, M.F. and J.A. Fordyce. 2003. Are induced defenses costly? Consequences of predator-induced defenses in western toads, Bufo boreas. Ecology 84(1):68-78.
- Billman, H.G., C.G. Kruse, S. St-Hilaire, T.M. Koel, J.L. Arnold, and C.R. Peterson. 2012. Effects of rotenone on Columbia spotted frogs Rana luteiventris during field applications in lentic habitats of southwestern Montana. North American Journal of Fisheries Management 32(4):781-789.
- Billman, H.G., S. St-Hilaire, C.G. Kruse, T.S. Peterson, and C.R. Peterson. 2011. Toxicity of the piscicide rotenone to Columbia spotted frog and boreal toad tadpoles. Transactions of the American Fisheries Society 140:919-927.
- Black, J.H. 1967a. Toads of Montana. Montana Wildlife 1967(Spring): 22-28.
- Black, J.H. 1970d. Some aspects of the distribution, natural history and zoogeography of the toad genus Bufo in Montana. M.S. thesis. University of Montana, Missoula, MT. 70 p.
- Black, J.H. 1970d. Unusual forms of boreal toads (Bufo boreas boreas) in Glacier National Park, Montana. Proceedings of the Oklahoma Academy of Science 50: 127-128.
- Blair, A.P. 1951. Note on the herpetology of the Elk Mountains, Colorado. Copeia 1951: 239-240.
- Blaustein, A.R., J.J. Beatty, H. Deanna, and R.M. Storm. 1995. The biology of amphibians and reptiles in old-growth forests in the Pacific Northwest. General Technical Report PNW-GTR-337. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 98 p.
- Blaustein, A.R., J.M. Romansic, and E.A. Scheessele. 2005. Ambient levels of ultraviolet-B radiation cause mortality in juvenile western toads, Bufo boreas. American Midland Naturalist 154(2):375-382.
- Blaustein, A.R., K.S. Chang, H.G. Lefcort and R.K. O'Hara 1990. Toad tadpole kin recognition: recognition of half siblings and the role of maternal cues. Ethology, Ecology and Evolution 2(2): 215-226.
- Boundy, J. and T.G. Balgooyen. 1988. Record lengths for some amphibians and reptiles from the western United States. Herpetological Review 19(2): 26-27.
- Brodie, E.D. 1968. A case of interbreeding between Bufo boreas and Rana cascadae. Herpetologica 24: 86.
- Brown, H.A. 1977. A case of interbreeding between Rana aurora and Bufo boreas (Amphibia, Anura). Journal of Herpetology 11(1): 92-94.
- Brunson, R.B. 1955. Check list of the amphibians and reptiles of Montana. Proceedings of the Montana Academy of Sciences 15: 27-29.
- Bull, E.L. and B.C. Wales. 2004. Movements of Western Toads in burned and unburned forests in northeastern Oregon. Abstract. Northwestern Naturalist 85:69.
- Burger, W.L., and A.N. Bragg. 1947. Notes on Bufo boreas (Baird and Girard) from the Gothic region of Colorado. Proceedings of the Oklahoma Academy of Sciences 27: 61-65.
- Campbell, J.B. 1970d. New elevational records for the boreal toad (Bufo boreas boreas). Arctic and Alpine Research 2: 157-159.
- Campbell, J.B. 1972. Reproduction and transformation of Boreal toads in the Colorado Front Range. Journal of the Colorado-Wyoming Academy of Science 7:114.
- Campbell, J.B. 1976. Environmental controls on boreal toad populations in the San Juan Mountains. Pp. 289-295. In: Ecological impacts of snowpack augmentation in the San Juan Mountains, Colorado. Steinhoff, H.W., and J.D. Ives (eds.). Final Report S
- Campbell, J.B. 1976. Environmental controls on boreal toad populations in the San Juan Mountains. Pp. 289-295. In: Ecological impacts of snowpack augmentation in the San Juan Mountains, Colorado. Steinhoff, H.W., and J.D. Ives (eds.). Final Report San Juan Ecology Project, Colorado State University Publications, Fort Collins.
- Campbell, J.B., and W.G. Degenhardt. 1971. Bufo boreas in New Mexico. Southwestern Naturalist 16(2): 219.
- Carey, C. 1976. Thermal physiology and energetics of boreal toads, Bufo boreas boreas. Ph.D. thesis. University of Michigan, Ann Arbor, Michigan.
- Carey, C. 1978. Factors affecting body temperatures of toads. Oecologia 35: 197-219.
- Carey, C. 1979a. Aerobic and anaerobic energy expenditure during rest and activity in montane Bufo b. boreas and Rana pipiens. Oecologia 39: 213-228.
- Carey, C. 1979b. Effect of constant and fluctuating temperatures on resting and active oxygen consumption of toads, Bufo boreas. Oecologia 39: 201-212.
- Carey, C. 1987. Status of a breeding population of the western toad (Bufo boreas boreas) at Lagunitas Campground, New Mexico. New Mexico Department of Game and Fish Contract # 516-74-26: 1-23.
- Carey, C. 1994. A matter of time: response to Aguirre. Conservation Biology 8: 7-8.
- Carey, C., B.C. Omundson, H. Ramsdell, L. Livo, and S. Brinkman. 1999. Disappearance of boreal toads in Colorado: a contaminant investigation. U.S. Fish and Wildlife Service, Grand Junction, CO.
- Carey, C., P.S. Corn, M.S. Jones, L.J. Livo, E. Muths, and C.W. Loeffler. 2005. Factors limiting the recovery of boreal toads (Bufo b. boreas). Pp. 222-236. In: Lannoo, M.J. (ed), Amphibian declines: the conservation status of United States species.
- Carlson, J. (Coordinator, Montana Animal Species of Concern Committee). 2003. Montana Animal Species of Concern. Helena, MT: Montana Natural Heritage Program and Montana Fish, Wildlife, and Parks. In Press. 12p.
- Carlton, J. 1993. BLF petitions to protect western boreal toad. Wild Earth 3(3): 14-15.
- Carpenter, C.C. 1953c. An ecological survey of the herpetofauna of the Grand Teton-Jackson Hole area of Wyoming. Copeia 1953: 170-174.
- Chestnut, T. and C.M. Crisafulli. 2005. Mate selection in Western toads (Bufo boreas). Abstract. Northwestern Naturalist 86:88.
- Chivers, D.P., J.M. Kiesecker, A. Marco, E.L. Wildy, and A.R. Blaustein. 1999. Shifts in life history as a response to predation in western toads (Bufo boreas). Journal of Chemical Ecology 25: 2455-2463.
- Chivers, D.P., J.M. Kiesecker, E.L. Wildy, L.K. Belden, L.B. Kats, and A.R. Blaustein. 1999. Avoidance response of post-metamorphic anurans to cues of injured conspecifics and predators. Journal of Herpetology 33(3): 472-476.
- Clark, R.J., C.R. Peterson, and P.E. Bartelt. 1993. The distribution, relative abundance, and habitat associations of amphibians on the Targhee National Forest. Final Report to the Targhee National Forest.
- Confluence Consulting Inc. 2010. Montana Department of Transportation Wetland Mitigation Monitoring Reports (various sites). MDT Helena, MT.
- Cook, F.R. 1977. Records of the boreal toad from the Yukon and Northern British Columbia. Canadian Field Naturalist 91(2): 185-186.
- Cooper, J. G. 1869. The fauna of Montana Territory (concluded) III. Reptiles, IV Fish. American Naturalist 3(3):124-127
- Cope, E.D. 1872. Report on the recent reptiles and fishes of the survey, collected by Campbell Carrington and C.M. Dawes. pp. 467-469 In: F.V. Hayden, Preliminary report of the United States geological survey of Montana and portions of adjacent territories; being a fifth annual report of progress. 538 pp. 42nd Congress, 2nd Session, House Executive Document Number 326. Serial 1520.
- Cope, E.D. 1875. Check-list of North American Batrachia and Reptilia; with a systematic list of the higher groups, and an essay on geographical distribution. Based on the specimens contained in the U.S. National Museum. U.S. Natioanl Museum Bulletin 1: 1-104.
- Cope, E.D. 1889. The Batrachia of North America. Bulletin of the U.S. National Museum 34: 1-525, figs. 1-119, pls. 1-86.
- Corkran, C.C. 2002. Amphibian surveys in the backcountry of the Greater Yellowstone Ecosystem. Northwestern Naturalist 83(2):67-68.
- Corkran, C.C. and C. Thoms. 2006. Amphibians of Oregon, Washington, and British Columbia. 2nd Edition. Vancouver, B.C.: Lone Pine Publishing. 176 p.
- Corn, P.S., B.R. Hossack, E. Muths, D.A. Palta, C.R. Peterson, and A.L. Gallant. 2005. Status of amphibians on the Continental Divide: aurveys on a transect from Montana to Colorado, USA. Alytes 22(3-4):85-94.
- Coues, E. and H. Yarrow. 1878. Notes on the herpetology of Dakota and Montana. Bulletin of the U.S. Geological Geographic Survey of the Territories 4: 259-291.
- Crisafulli, C.M., L.S. Trippe, C.P. Hawkins, and J.A. MacMahon. 2005. Amphibian responses to the 1980 eruption of Mount St. Helens. Pp. 183-198 In: V.H. Dale, F.J. Swanson, and C.M. Crisafulli, (Eds). Ecological responses to the 1980 eruption of Mount
- Crisafulli, C.M., L.S.T. Kling, and A.P. McIntyre. 2005. The response of the Western toad (Bufo boreas) to the 1980 eruption of Mount St. Helens. Abstract. Northwestern Naturalist 86:89.
- Crother, B.I. (ed.) 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico. SSAR Herpetological Circular No. 37:1-84.
- Davis, T.M. and P.T. Gregory. 2003. Decline and local extinction of the Western Toad, Bufo boreas, on Southern Vancouver Island, British Columbia, Canada. Herpetological Review 34(4):350-352.
- Dickerson, K. 2002. Environmental contaminants program on-refuge investigations sub-activity, final report: year 3. Department of the Interior U.S. Fish and Wildlife Service, Nationwide Malformed Amphibian Monitoring Program. 21p. +Appendices A-G.
- Dole, J.W., B.B. Rose, and C.F. Baxter. 1985. Hyperosmotic saline environment alters feeding behavior in the western toad (Bufo boreas). Copeia 1985(3): 645-648.
- Dole, J.W., B.B. Rose, and K.H. Tachiki. 1981. Western toads (Bufo boreas) learn odor of prey insects. Herpetologica 37: 63-68.
- Eaton, B.R., C. Grekul, C. Paskowski. 1999. An oberservation of interspecific amplexus between boreal, Bufo boreas, and Canadian, B. hemiophrys, toads, with a range extension for the boreal toad in Alberta. Canadian Field Naturalist 113(3): 512-513.
- Eaton, B.R., C.L. Browne, C.A. Paszkowski, Z.C. Eaton, and R. Chapman. 2005. Bufo boreas (Western Toad). Herpetological Review 36(1):52.
- Engemann, R.M., and R.W. Connell. 1991. Boreal toad in Clear Creek County, Colorado. Northwestern Naturalist 71(3): 98.
- Enk, M. 1999. Preliminary results of amphibian monitoring on the Lewis & Clark National Forest. Intermountain Journal of Sciences 5(1-4): 48.
- Environmental Protection Agency. 23 March 1995. Federal Register 60(56): 15264-16268.
- Feder, J.H. 1977. Hybridization and genetic divergence in the toads Bufo boreas and Bufo punctatus. American Zoologist 17(4): 972.
- Feder, J.H. 1979. Natural hybridization and genetic divergence between the toads Bufo boreas and Bufo punctatus. Evolution 33(4): 1089-1097.
- Ferguson, D.E. 1954. An interesting factor influencing Bufo boreas reproduction at high elevations. Herpetologica 10: 199
- Fetcavitch, C. and L.J. Livo. 1999. Late-season boreal toad tadpoles. Northwestern Naturalist 79: 120-121.
- Fish, J.L. 1972. Growth and survival of anuran tadpoles (Bufo boreas and Rana aurora) in relation to acute gamma radiation, water temperature, and population density. Ph.D. Thesis, Washington State University. 91pp.
- Flath, D.L. 2002. Reptile and amphibian surveys in the Madison-Missouri River Corridor, Montana. Annual Progress Report. 14pp.
- Freda, J., V. Cavdek, and D.G. McDonald. 1990. Role of organic complexation in the toxicity of aluminum to Rana pipens embryos and Bufo americanus tadpoles. Canadian Journal of Fisheries and Aquatic Sciences 47: 217-224.
- Galloway, B.T. 2014. Feasibility assessment for translocation of imperiled Bull Trout populations in Glacier National Park, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 110 p.
- Garber, C. S. 1992. A survey for spotted frogs (Rana pretiosa), wood frogs (Rana sylvatica), and boreal toads (Bufo boreas) in Wyoming. Wyoming Natural Diversity Database, Laramie. 15 pp. + appendix.
- Garber, C.S. 1994. A status survey for spotted frogs (Rana pretiosa) wood frogs (Rana sylvatica) and boreal toads (Bufo boreas) in the mountains of southern and eastern Wyoming. U.S.F.W.S. Cooperative Agreement No. 14-48-0006-92-919.
- Garber, C.S. 1995a. A survey for U.S. Forest Service listed "Sensitive" amphibians including the spotted frog (Rana pretiosa), leopard frog (Rana pipiens), tiger salamander (Ambystoma tigrinum) and the boreal toad (Bufo boreas) on the north half of the
- Garber, C.S. 1995b. Addendum Number 1 to "A status survey for spotted frogs (Rana pretiosa) wood frogs (Rana sylvatica) and boreal toads (Bufo boreas) in the mountains of southern and eastern Wyoming. Unpublished report prepared by the Wyoming Natural
- Gittins, S.P., J.E. Steeds, and R. Williams. 1982. Population age-structure of the common toad (Bufo bufo) at a lake in mid-Wales determined from annual growth rings in the phalanges, British Journal of Herpetology 6:249-252.
- Goebel, A.M. 1997. Molecular genetic determination of management units of the endandered boreal toad (Bufo boreas) in Colorado and southeast Wyoming. Unpublished report, Colorado Division of Wildlife.
- Goebel, A.M. 2000. Genetic analysis of the southern Rocky Mountain group of Bufo boreas based on mitochondrial DNA sequence and nuclear AFLP restriction site data. In Jones, M.S. (ed.) Colorado Division of Wildlife Boreal Toad Research Progress 1999, A
- Goebel, A.M. 2005. Conservation systematics: the Bufo boreas species group. Pp. 210-221. In: Lannoo, M.J. (ed), Amphibian declines: the conservation status of United States species. University of California Press, Berkley, California.
- Goebel, A.M., T.A. Ranker, P.S. Corn, and R.G. Olmstead. 2009. Mitochondrial DNA evolution in the Anaxyrus boreas species group. Molecular Phylogenetics and Evolution 50:209-225.
- Goettl, J.P., Jr. 1997. Boreal toad (Bufo boreas) recovery plan (southern Rocky Mountain population). Colorado Division of Wildlife. 45 p.
- Gorman, R.R. and D.E. Ferguson. 1970. Sun-compass orientation in the western toad (Bufo boreas). Herpetologica 26(1): 34-45.
- Guscio, C.G., B.R. Hossack, L.A. Eby, and P.S. Corn. 2008. Post-breeding habitat use by adult boreal toads (Bufo boreas) after wildfire in Glacier National Park, USA.
- Hanauska-Brown, L., B.A. Maxell, A. Petersen, and S. Story. 2014. Diversity Monitoring in Montana 2008 – 2010 Final Report. Montana Fish, Wildlife & Parks. Helena, MT. 78 pp.
- Hawkes, V.C. and M.A. Fraker. 2000. Observations of amphibians in the floodplain of a regulated northern river. Northwestern Naturalist 81(2):75.
- Hayes, M.P. and C.B. Hayes. 2004. Bufo boreas boreas (Boreal Toad). Scats and Behavior. Herpetological Review 35(4):369-370.
- Hayes, T.B. 1995. Histological examination of the effects of corticosterone in larvae of the western toad, Bufo boreas (Anura: Bufonidae), and the Oriental fire-bellied toad, Bombina orientalis (Anura: Discoglossidae). Journal of Morphology 226(3):297-307.
- Hayes, T.B. and P. Licht. 1995. Factors influencing testosterone metabolism by anuran larvae. Journal of Experimental Zoology 271(2): 112-119.
- Hayes, T.B. and T.H. Wu. 1995. Interdependence of corticosterone and thyroid hormones in toad larvae (Bufo boreas). 2. Regulation of corticosterone and thyroid hormones. Journal of Experimental Zoology 271(2): 103-111.
- Hayes, T.B. and T.N. Gill. 1995. Hormonal regulation of skin gland development in the toad (Bufo boreas): the role of the thyroid hormones and corticosterone. Genetics and Comparative Endocrinology 99(2): 161-168.
- Hayes, T.B., R. Chan, and P. Licht. 1993. Interactions of temperature and steroids on larval growth, development, and metamorphosis in a toad (Bufo boreas). Journal of Experimental Zoology 266(3): 206-215.
- Hendricks, P. 1997. Lee Metcalf National Wildlife Refuge preliminary amphibian and reptile investigations: 1996. Montana Natural Heritage Program, Helena, MT. 21 p.
- Hendricks, P. 1999. Amphibian and reptile survey of the Bureau of Land Management Miles City District, Montana. Montana Natural Heritage Program, Helena, MT. 80 p.
- Hendricks, P. 2000. Amphibian and reptile survey of the Thompson Chain of Lakes. A report to the Montana Department of Fish, Wildlife, and Parks. Montana Natural Heritage Program, Helena, MT. 15 p.
- Herreid, C.F., II. 1963. Range extension for Bufo boreas boreas. Herpetologica 19(3): 218.
- Hews, D.K. 1988. Alarm response in larval western toads, Bufo boreas: release of larval chemicals by a natural predator and its effect on predator capture efficiency. Animal Behaviour 36: 125-133.
- Hews, D.K. and A.R. Blaustein. 1985. An investigation of the alarm response in Bufo boreas and Rana cascadae. Behavior and Neural Biology 43: 47-57.
- Hill, S.R. and R.E. Moore. 1994. Herpetological survey in the northern range of Yellowstone National Park. Annual Report, Yellowstone National Park. February 1, 1994. 21 pp.
- Hill, S.R., Jr. and R.E. Moore. 1994a. Herpetological survey in the northern range of Yellowstone National Park. Investigator's Annual Reports Yellowstone National Park 1993. Yellowstone Center for Resources. pp. 96-97.
- Hilliard, J., H. Minkus, and M. Weber. 1997. Amphibian survey of the Birch Creek drainage, Beaverhead County. Wildland Studies Project, San Francisco State University, San Francisco, CA. 12 p.
- Hillman, S.S. 1980. Physiological correlates of differential dehydration tolerance in anuran amphibians. Copeia 1980(1):125-129.
- Horstman, G.P. 1998. Beetle and toad: an analysis of the predator-prey relationship of the predacious (sic) diving beetle (Coleoptera: Dytiscidae) and Colorado's endangered boreal toad (Bufo boreas boreas). Bulletin of the Chicago Herpetological Societ
- Hossack, B., D. Pilliod, and P.S. Corn. 2001a. Reptile and amphibian inventory at Grant-Kohrs Ranch National Historic Site and Little Bighorn Battlefield National Monument. USGS Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, Missoula, MT. 6 p.
- Hossack, B., D. Pilliod, and P.S. Corn. 2001b. Preliminary amphibian surveys of the National Bison Range, Lost Trail National Wildife Refuge, and Swan River National Wildlife Refuge: 2001. USGS Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, Missoula, MT. 15 p.
- Hossack, B.R. 2006. Amphibians and wildfire in the U.S. Northwest. International Journal of Wilderness 12(1):26.
- Hossack, B.R. and P.S. Corn. 2004. Responses of pond-breeding amphibians to wildfire in Glacier National Park. Abstract. Northwestern Naturalist 85:78.
- Hossack, B.R. and P.S. Corn. 2008. Wildfire effects on water temperature and selection of breeding sites by the boreal toad (Bufo boreas) in seasonal wetlands. Herpetological Conservation and Biology 3:46-54.
- Hossack, B.R., S.A. Diamond, and P.S. Corn. 2006. Distribution of boreal toad populations in relation to estimated UV-B dose in Glacier Naitonal Park, Montana, USA. Canadian Journal of Zoology 84:98-107.
- Hossack,B.R., W.R. Gould, D.A. Patla, E. Muths, R. Daley, K. Legg, and P.S. Corn. 2015. Trends in Rocky Mountain amphibians and the role of beaver as a keystone species. Biological Conservation 187:260-269.
- Hubbard, J. D. 1972. Some aspects of geographic variation in the Boreal toad, Bufo boreas boreas. Journal of the Colorado-Wyoming Academy of Science 7(2): 65-66.
- Huey, R.B. 1980. Sprint velocity of tadpoles (Bufo boreas) through metamorphosis. Copeia 1980(3):537-540.
- Huey, R.B. and R.D. Stevenson. 1979. Integrating thermal physiology and ecology of ectotherms: a discussion of approaches. American Zoologist 19(1): 357-366.
- Humphris, Michael., 1993, Wildlife Monitoring Report. Spring Creek Coal Company 1993 Mining Annual Report. Appendix I. April 11, 1993.
- Humphris, Michael., 1994, Wildlife Monitoring Report. Spring Creek Coal Company 1994 Mining Annual Report. Appendix I. April 1994.
- James, M.T. and T.P. Maslin 1947. Notes on myiasis of the toad, Bufo boreas boreas Baird and Girard. Journal of the Washington Academy of Science 37(10): 366-368.
- Jennings, M.R., J.J. Crayon, and R.L. Hothem. 2005. Bufo boreas halophilus (California Toad) and Rana catesbeiana (American Bullfrog). Amplexus. Herpetological Review 36(1):53.
- Johnson, P.T.J., K.B. Lunde, E.M. Thurman, E.G. Ritchie, S.N. Wray, D.R. Sutherland, J.M. Kapfer, T.J. Frest, J. Bowerman, and A.R. Blaustein. 2002. Parasite (Ribeiroia ondatrae) infection linked to amphibian malformations in the western United States. Ecological Monographs 72(2):151-168.
- Johnson, P.T.J., K.B. Lunde, R.W. Haight, J. Bowerman, and A.R. Blaustein. 2001. Ribeiroia ondatrae (Trematoda: Digenea) infection induces severe limb malformations in western toads (Bufo boreas) Canadian Journal of Zoology 79: 370–379.
- Jones, K.L. 1978. Status of Bufo boreas in New Mexico. Report to New Mexico Department of Game and Fish, Contract # 519-66-8. 9pp.
- Jones, Lawrence L. C., W. P. Leonard and D. H. Olson, eds. 2005. Amphibians of the Pacific Northwest. Seattle Audubon Society: Seattle, WA, 227 pp.
- Jones, M.S. (ed.). 1998. Boreal toad research progress report 1998. Colorado Division of Wildlife. 116 pp.
- Jones, M.S. (ed.). 2000. Boreal toad research progress report: 1999. April, 2000. Unpublished report. Colorado Division of Wildlife, Ft. Collins. 157 pp.
- Jones, M.S. and B. Stiles. 2000. Bufo boreas (Boreal Toad) Predation. Herpetological Review 31(2): 99.
- Jones, M.S. and J.P. Goettl. 1998. Henderson/Urad boreal toad studies. Pp. 21-82 In: Boreal Toad Research Progress Report, 1995-1997. Colorado Division of Wildlife.
- Jordan, J.D., C.J. Rombough, C.A. Pearl, and B. McCreary. 2004. Cannibalism and predation by western toad (Bufo boreas boreas) larvae in Oregon, USA. Western North American Naturalist 64(3):403-405.
- Keinath, D. and J. Bennett. 2000. Distribution and status of the boreal toad (Bufo boreas boreas) in Wyoming. Wyoming Natural Diversity Database. University of Wyoming, Laramie, Wyoming. 23 pp.
- Kiesecker, J. M., A. R. Blaustein, and C. L. Miller. 2001. Transfer of a pathogen from fish to amphibians. Conservation Biology 15:1064-1070.
- Kiesecker, J.M., D.P. Chivers, and A.R. Blaustein. 1996. The use of chemical cues in predator recognition by western toad tadpoles. Animal Behaviour 52(6): 1237-1245.
- Koch, E.D. and C.R. Peterson. 1989. A preliminary survey of the distribution of amphibians and reptiles in Yellowstone National Park. pp. 47-49. In: Rare, sensitive and threatened species of the Greater Yellowstone Ecosystem, T.W. Clark, A.H. Harvey, R.D. Dorn, D.C. Genter, and C. Groves (eds.), Northern Rockies Conservation Cooperative , Montana Natural Heritage Program, The Nature Conservancy, and Mountain West Environmental Services. 153 p.
- Koller, R.L., and A.J. Gaudin. An analysis of helminth infections in Bufo boreas (Amphibia: Bufonidae) and Hyla regilla (Amphibia: Hylidae) in southern California. Southwestern Naturalist 21(4): 503-509.
- Kruse, K.C. 1983. Optimal foraging by predacious diving beetle larvae on toad tadpoles. Oecologia 58: 383-388.
- Lambert, B., C.R. Malleck, and B. Christman. 1999. Boreal toad surveys in Colorado: summer 1999. Prepared by the Colorado Natural Heritage Program for the Colorado Division of Wildlife and the U.S. Forest Service. 22 pp.
- Lambert, B., C.R. Malleck, and K. Huhn. 2000. Boreal toad survey and monitoring project: 2000. Prepared by the Clorado Natural Hertiage Program for the Colorado Division of Wildlife and the U.S. Forest Service. 59pp. + appendices.
- Laselle, B.T. 2000. Association of wetland area with breeding activity for multiple amphibian species. Undergraduate Honors Thesis. Carroll College, Helena, MT. 18 p.
- Licht, L.E. 1968. Unpalatability and toxicity of toad eggs. Herpetologica 24: 93-98.
- Livezey, R.L. 1960. Description of the eggs of Bufo boreas exsul. Herpetologica 16:48.
- Livo, L.J. 1998a. Investigations of boreal toad (Bufo boreas) tadpole ecology. Pp. 115-146 In: Boreal Toad Research Progress Report, 1995-1997. Colorado Division of Wildlife.
- Livo, L.J. 1998b. Predators of larval Bufo boreas. Colorado-Wyoming Academy of Science 38: 32.
- Livo, L.J. 1999. The role of predation in the early life history of Bufo boreas in Colorado. Ph.D. Dissertation, University of Colorado, Boulder. 197 pp.
- Livo, L.J. 1998a. Investigations of boreal toad (Bufo boreas) tadpole ecology. Pp. 115-146 In: Boreal Toad Research Progress Report, 1995-1997. Colorado Division of Wildlife.
- Livo, L.J. and B.A. Lambert. 2001. Bufo boreas (boreal toad) phoretic host. Herpetological Review 32(3): 179-180.
- Livo, L.J. and C. Fetkavich. 1998. Late-season boreal toad tadpoles. Northwestern Naturalist 79: 120-121.
- Livo, L.J., and D. Yeakley. 1997. Comparison of current with historical elevational range in the boreal toad, Bufo boreas. Herpetological Review 28(3): 143-144.
- Loeffler, C. 2002. Conservation plan and agreement for the management and recovery of the southern Rocky Mountain population of the boreal toad (Bufo boreas boreas). San Miguel Headwaters--Valley Floor. Volume 2: appendices: 150pp.
- Loeffler, C. (ed). 2001. Conservation plan and agreement for the management and recovery of the southern Rocky Mountain population of the Boreal toad (Bufo boreas boreas). Boreal Toad Recovery Team. 97 p.
- Loeffler, C. (ed.). 1999. Report on the status and conservation of the boreal toad (Bufo boreas boreas) in the Southern Rocky Mountains. Boreal Toad Recovery Team. 51pp.
- Loeffler, C. (ed.). 2000. Report on the status and conservation of the boreal toad (Bufo boreas boreas) in the Southern Rocky Mountains. Boreal Toad Recovery Team. 58pp.
- Long, C.A. 1964. The badger as a natural enemy of Ambystoma tigrinum and Bufo boreas. Herpetologica 20(2): 144.
- Manis, M.L. 1981. The effects of the presence of conspecifics on the feeding behavior of three species of bufonid anurans. M.S. Thesis, Adelphi University. 52p.
- Manville, R.H. 1957. Amphibians and reptiles of Glacier National Park, Montana. Copeia 1957: 308-309.
- Marco, A., J.M. Kiesecker, D.P. Chivers, and A.R. Blaustein. 1998. Sex recognition and mate choice by male western toads (Bufo boreas). Animal Behaviour 55: 1631-1635.
- Marnell, L.F. 1996. Amphibian survey of Glacier National Park, Montana. Abstract. Intermountain Journal of Sciences 2(2): 52.
- Martin, D.L. 1988. Bufo boreas halophilus length record. Herpetological Review 19(2): 26.
- Martin, P.R. 1980a. Terrestrial wildlife habitat inventory in southeastern Montana. Montana Department of Fish, Wildlife and Parks and Bureau of Land Management, Helena MT. 114 p.
- Martin, P.R., K. Dubois and H.B. Youmans. 1981. Terrestrial wildlife inventory in selected coal areas, Powder River resources area final report. Montana Department of Fish, Wildlife and Parks and Bureau of Land Management, Helena, MT. No. YA-553-CTO- 24. 288 p.
- Maxell, B.A. 2002a. Amphibian and aquatic reptile inventories in watersheds in the South and Middle Forks of the Flathead River drainage that contain lakes being considered for application of piscicides and subsequent stocking of west slope cutthroat trout. Report to the Region 1 Office of the U.S. Forest Service and the Montana Department of Fish, Wildlife, and Parks. Montana Cooperative Wildlife Research Unit and Wildlife Biology Program, University of Montana, Missoula, MT. 62 pp.
- Maxell, B.A. 2016. Flammulated Owl surveys on the Big Timber, Bozeman, Gardiner and Livingston Ranger Districts of the Custer Gallatin National Forest: 2013. Report to Custer Gallatin National Forest. Montana Natural Heritage Program. Helena, MT. 27pp + appendices.
- McCaffery, R., R.E. Russell, B.R. Hossack. 2021. Enigmatic near-extirpation in a boreal toad metapopulation in northwestern Montana. The Journal of Wildlife Management 85(5):953-963.
- Meis, N.J. 1999. The effects of mining effluent on amphibian breeding behavior and survival. Undergraduate Honors Thesis. Carroll College, Helena, MT. 21 p.
- Miller, M. 1995. Amphibian survey Birch Creek July 1995. Wildland Studies Project, San Francisco State University, San Francisco, CA. 9 p.
- Miller, M. 1995. Amphibians survey, Birch Creek, July 1995. Unpublished report. University of California, Berkley. 3 pp.
- Morton, M.L., and K.N. Sokolski. 1978. Sympatry in Bufo boreas and Bufo canorus and additional evidence of natural hybridization. Bulletin of the Southern California Academy of Sciences 77: 52-55.
- Mullally, D.P. 1956. The relationships of the Yosemite and western toads. Herpetologica 12: 133-135.
- Mullally, D.P., and D.H. Powell. 1958. The Yosemite toad: northern range extension and possible hybridization with the western toad. Herpetologica 14: 31-34.
- Muths, E. 2003. Home range and movements of boreal toads in undisturbed habitat: Copeia 2003: 160-165.
- Muths, E. and P.S. Corn. 1997. Basking by adult boreal toads (Bufo boreas boreas) during the breeding season. Journal of Herpetology 31: 426-428.
- Muths, E. and P.S. Corn. 2000. Boreal toad In: Endangered animals, a reference guide to conflicting issues. R.P. Reading and B. Miller (eds.) Greenwood Press, Westport CT. Pp. 60-65.
- Muths, E., P.S. Corn, A.P. Pessier, and D.E. Green. 2003. Evidence for disease-related amphibian decline in Colorado. Biological Conservation 110: 357-365.
- Muths, E., P.S. Corn, and T.R. Stanley. 2000. Use of Oxytetracycline in batch-marking post-metamorphic boreal toads. Herpetological Review 31(1): 28-32.
- Muths, E., T.L. Johnson, and P.S. Corn. 2001. Experimental repatriation of boreal toad (Bufo boreas) eggs, metamorphs, and adults in Rocky Mountain National Park. Southwestern Naturalist 46(1): 106-113.
- Nesler, T.P. and J.P. Goettl. 1994. Boreal toad recovery plan, Colorado Division of Wildlife, Denver, Colorado. 22 pp. plus appendices
- Norman, B.R. 1988. Geographic distribution. Bufo boreas boreas (boreal toad). Herpetological Review 19(1): 16.
- Northrop, Devine and Tarbell, Inc. 1995. Cabinet Gorge and Noxon Rapids Hydroelectric Developments, 1994 Wetland Mapping and Assessment Study, Volume I of II. 27 pp. plus appendices.
- Oechsli, L.M. 2000. Ex-urban development in the Rocky Mountain West: consequences for native vegetation, wildlife diversity, and land-use planning in Big Sky, Montana. M.Sc. Thesis. Montana State University, Bozeman. 73 p.
- O'Hara, R.K. 1981. Habitat selection behavior in three species of anuran larvae: environmental cues, ontogeny, and adaptive significance. Ph.D. dissertation, Oregon State University. Corvallis, Oregon. 154 pp.
- O'Hara, R.K. and A.R. Blaustein. 1982. Kin preference behavior in Bufo boreas tadpoles. Behavioral Ecology and Sociobiology 11: 43-49.
- Olson, D.H. 1991. Ecological susceptibility of amphibians to population declines. Proceedings of the Symposium on Biodiversity of Northwestern California, October 28-30: 55-62.
- Olson, D.H. 1992a. Ecological susceptibility of amphibians to population declines. In: Harris R.R., D.E. Erman (tech. Coordinators) and H.M. Kerner (ed.). Proceedings of symposium on biodiversity of northwestern California. Davis, CA: University of California Wildland Resources Center. Report 29. p. 55-62.
- Olson, D.H., A.R. Blaustein, and R.K. O'Hara. 1986. Mating pattern variability among western toad (Bufo boreas) populations. Oecologia 70: 351-356.
- Patla, D.A. 1998a. Amphibians and reptiles in the Old Faithful sewage treatment area. Report to Yellowstone Center for Resources, Yellowstone National Park. 10 September, 1998. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 7 p.
- Patla, D.A. 1998b. Potential effects of native fish restoration projects on amphibians in Yellowstone National Park Part I. Report to National Park Service, Yellowstone National Park. 20 November 1998. 26 pp.
- Patla, D.A. 1999a. Amphibians and reptiles along the grand loop road in Yellowstone National Park: Canyon Junction to Fishing Bridge Junction. December 11, 1999. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 24 p.
- Patla, D.A. 1999b. Amphibians and reptiles of the Madison to Norris road improvement project area, Yellowstone National Park. 11 November, 1999. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 17 p.
- Patla, D.A. 2000. Amphibians in potential native fish restoration areas, Yellowstone National Park Part II. 7 March, 2000. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 22 p.
- Patla, D.A. 2001. Conservation assessment for the boreal toad (Bufo boreas boreas) on the Bridger-Teton National Forest, Wyoming. 27 March, 2001. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 44 p.
- Patla, D.A. and C.R. Peterson. 1996a. Amphibians and reptiles along the Grand Loop Highway in Yellowstone National Park: Tower Junction to Canyon Village. 24 February, 1996. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 49 p.
- Patla, D.A. and C.R. Peterson. 1996b. Amphibians and reptiles along the Grand Loop Highway in Yellowstone National Park: Arnica Creek to Little Thumb Creek. 1 August, 1996. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 35 p.
- Patla, D.A. and C.R. Peterson. 1997. Amphibians and reptiles along the Grand Loop Highway in Yellowstone National Park: Mammoth Hot Springs to Norris Junction. 1 February, 1997. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 60 p.
- Patla, D.A. and C.R. Peterson. 1998. Amphibians of the Greater Yellowstone Ecosystem. Natural Resource Conservation Cooperative News 11(Autumn 1998): 10-11.
- Patla, D.A. and C.R. Peterson. 1999. Are amphibians declining in Yellowstone National Park? Yellowstone Science 1999 (Winter):2-11.
- Patla, D.A. and C.R. Peterson. 2001. Status and trends of amphibian populations in the Greater Yellowstone Ecosystem, progress report, February 2001. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 8 p.
- Pearl, C.A. 2000. Bufo boreas (western toad) predation. Herpetological Review 31:233-234.
- Pearl, C.A. and J. Bowerman. 2006. Observations of rapid colonization of constructed ponds by western toads (Bufo boreas) in Oregon, USA. Western North American Naturalist 66(3): 397-401.
- Pearl, C.A.and M.P. Hayes. 2002. Predation by Oregon spotted frogs (Rana pretiosa) on western toads (Bufo boreas) in Oregon. American Midland Naturalist 147(1): 145-152.
- Pearson, A.K., T.B. Hayes, and P. Licht. 1998. Immunochemical identification of thyrotropes and gonadotropes in the pars distalis and pars tuberalis of the toad (Bufo boreas) with reference to ontogenic changes. General and Comparative Endocrinology 111:83-94.
- Peterson, C.R. and J.P. Shive. 2002. Herpetological survey of southcentral Idaho. Idaho Bureau of Land Management Technical Bulletin 02-3:1-97.
- Peterson, C.R., C.J. Askey, and D.A. Patla. 1993. Amphibians and reptiles along the Grand Loop and Fountain Freight Roads between Madison Junction and Biscuit Basin in Yellowstone National Park. 26 July, 1993. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 45 p.
- Peterson, C.R., D.A. Patla, and S.R. Sullivan. 1995. Amphibians and reptiles along the Grand Loop Highway in Yellowstone National Park: Madison Junction to Norris Campground. 7 July, 1995. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 64 p.
- Peterson, C.R., E.D. Koch and P.S. Corn. 1992. Monitoring amphibian populations in Yellowstone and Grand Teton National Parks final report to University of Wyoming. National Park Service Research Center, Laramie, WY. 37 p.
- Putnam, R.W. 1979. The basis for differences in lactic acid content after activity in different species of anuran amphibians. Physiological Zoology 52(4): 509-519.
- Putnam, R.W. and A.F. Bennett. 1981. Thermal dependence of behavioural performance of anuran amphibians. Animal Behaviour 29(2): 502-509.
- Putnam, R.W. and S.S. Hillman. 1977. Activity responses of anurans to dehydration. Copeia 1977(4): 746-749.
- Reichel, J. and D. Flath. 1995. Identification of Montana's amphibians and reptiles. Montana Outdoors 26(3):15-34.
- Reichel, J. D. In prep. Amphibian and reptile survey in southwest Montana: 1996. Unpublished report.
- Reichel, J.D. 1997a. Amphibian, reptile and northern bog lemming survey on the Rocky Mountain Front: 1996. Montana Natural Heritage Program, Helena, MT. 81 p.
- Reichel, J.D. and S.G. Beckstrom. 1993. Northern bog lemming survey: 1992. Unpublished report. Montana Natural Heritage Program, Helena, MT. 64 p.
- Reinhard, E.G. 1930b. Miscellaneous note on Bufo boreas. Yellowstone Nature Notes 7(7): 46.
- Roberts, B. 2010. 2009 Hebgen Basin Reptile and Amphibian Inventory, USDA Forest Service Annual Progress Report to PPL-Montana. Gallatin National Forest, Bozeman Ranger District. Bozeman, MT. 23 pp.
- Robinson, M., M.P. Donovan, and T.D. Schwaner. 1998. Western toad (Bufo boreas) in southern Utah: notes on a single population along the east fork of the Sevier River. Great Basin Naturalist 58(1): 87-89.
- Roedel, M.D. and P. Hendricks. 1998. Amphibian and reptile survey on the Bureau of Land Management Lewistown District: 1995-1998. Montana Natural Heritage Program, Helena, MT. 53 p.
- Roedel, M.D. and P. Hendricks. 1998b. Amphibian and reptile inventory on the Headwaters and Dillon Resource Areas in conjunction with Red Rocks Lakes National Wildlife Refuge: 1996-1998. Montana Natural Heritage Program, Helena, MT. 46 p.
- Rogers, K., A. Schmidt, J. Wilkinson, and T. Merz. 2001. Effects of incidental UV-B radiation on periphyton in four alpine freshwater ecosystems in central Colorado: impacts on boreal toad tadpoles (Bufo boreas). Journal of Freshwater Ecology 16: 283-3
- Rogers, M.W.. Jr. 1975. Development and behavior of larvae of the western toad (Bufo boreas). M.A. Thesis, University of Texas, Arlington. 68p.
- Savage, J.M. and F.W. Schuierer. 1981. The eggs of toads of the Bufo boreas group, with descriptions of the eggs of Bufo exsul and Bufo nelsoni. Bulletin of the Southern California Academy of Science 60: 93-99.
- Scherff-Norris, K.L. 1997. Hatchery manual for the rearing and propagation of captive boreal toads, Bufo boreas. Colorado Division of Wildlife. 21 pp.
- Scherff-Norris, K.L. 1999. Final Report: experimental reintroduction of boreal toads (Bufo boreas boreas). Colorado Division of Wildlife. 32pp.
- Schmetterling, D.A. and M.K. Young. 2008. Summer movements of boreal toads (Bufo boreas boreas) in two western Montana basins. Journal of Herpetology 42:111-123.
- Schueler, F.W. 1982b. Sexual colour differences in Canadian western toads, Bufo boreas. Canadian Field Naturalist 96(3): 329-332.
- Schuierer, F.W. 1962. Notes on two populations of Bufo exsul Myers and a commentary on speciation within the Bufo boreas group. Herpetologica 18(4): 262-267.
- Sestrich, C. 2004. Hebgen Reservoir amphibian survey. USDA Forest Service Annual Progress Report to PPL Montana. 22pp.
- Sestrich, C. 2004. Hebgen Reservoir Amphibian Survey: USDA Forest Service annual progress report to PPL Montana. 17 pp + appendix
- Sestrich, Clint. 2006. 2006 Hebgen Reservoir Amphibian Survey, USDA Forest Service Annual Progress Report to PPL Montana. Hebgen Lake Ranger District. Gallatin National Forest. West Yellowstone Montana.
- Shinn, E.A. and J.W. Dole. 1979a. Evidence for a role for olfactory cues in the feeding response of western toads (Bufo boreas). Copeia 1979(1): 1663-165.
- Shinn, E.A. and J.W. Dole. 1979b. Lipid components of prey odors elicit feeding responses in western toads (Bufo boreas). Copeia 1979(2): 275-278.
- Sivula, J.C., M.C. Mix, and D.S. McKenzie. 1972. Oxygen consumption of Bufo boreas boreas tadpoles during various developmental stages of metamorphosis. Herpetologica 28(4): 309-313.
- Skinner, M.P. 1924. The Yellowstone Nature Book. A.C. McClurg Company, Chicago, IL. 221 p.
- Smits, A.W. and D.L Crawford. 1984. Emergence of toads to activity: a statistical analysis of contributing cues. Copeia 1984(3): 696-701.
- Spring Creek Coal Company., 1992, Wildlife Monitoring Report. Spring Creek Coal Company 1992 Mining Annual Report. Appendix I.
- Stearns-Roger Inc., 1975, Environmental baseline information of the Mount Vernon Region, Montana. January 31, 1975.
- Stebbins, R.C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Company, Boston. 336 pp.
- Stiverson, R.K. and G.C. Packard. 1974. The relation of blood hemoglobin concentration to body size in the boreal toad Bufo boreas. Journal of the Colorado-Wyoming Academy of Science 7(5): 77.
- Stoyke, G. 1994. How to attract toads. Alberta Naturalist 24(1): 5.
- Sullivan, S.R. and C.R. Peterson. 1996. Amphibians and reptiles along the highway in Yellowstone National Park: Tower Junction to the Northeast Entrance. 25 February, 1996. Greater Yellowstone Ecosystem Amphibian Survey and Monitoring Program, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID. 60 p.
- Syslo, J. and L. Eby. 2005. Possible effects of Highway 93 expansion on a population of Western toads (Bufo boreas) in the Bitterroot Valley. Wildlife Biology Program University of Montana. pp. 11 plus figures.
- Thompson, M.D. and A.P. Russell. 2000. Phylogeography of Ambystoma macrodactylum: post glacial range expansion and resultant genetic diversity. Field Summary Report No. 1. University of Calgary. Calgary, Canada. 39 p.
- Thompson, P.D. 2004. Observations of boreal toad (Bufo boreas) breeding populations in northwestern Utah. Herpetological Review 35(4):342-344.
- Thompson, P.D., R.A. Fridell, K.K. Wheeler, and C.L. Bailey. 2004. Distribution of Bufo boreas in Utah. Herpetological Review 35(3):255-257.
- Thompson, Richard W., Western Resource Dev. Corp., Boulder, CO., 1996, Wildlife baseline report for the Montana [Montanore] Project, Lincoln and Sanders counties, Montana. In Application for a Hard Rock Operating Permit and Proposed Plan of Operation, Montanore Project, Lincoln and Sanders Counties, Montana. Vol. 5. Stroiazzo, John. Noranda Minerals Corp., Libby, MT. Revised September 1996.
- Tiekotter, K.L. 1977. A study of trematodes collected from toads of a Colorado alpine meadow. Proceedings of the Nebraska Academy of Science and Afiliated Societies 87:22.
- Timken, R. No Date. Amphibians and reptiles of the Beaverhead National Forest. Western Montana College, Dillon, MT. 16 p.
- Tracy, C.R. and J.W. Dole. 1969b. Orientation of displaced California toads (Bufo boreas) to their breeding sites. Copeia 1969(40): 693-700.
- Turner, F.B. 1951. A checklist of the reptiles and amphibians of Yellowstone National Park with incidental notes. Yellowstone Nature Notes 25(3): 25-29.
- Turner, F.B. 1955. Reptiles and amphibians of Yellowstone National Park. Yellowstone Interpretive Series No. 5. Yellowstone Library and Museum Association. Yellowstone National Park, WY. 40 p.
- Turner, F.B. 1957. The ecology and morphology of Rana pretiosa pretiosa in Yellowstone Park, Wyoming. Ph.D. dissertation, University of California. Berkeley, CA. 252 pp.
- Turner, F.B. 1960. Population structure and dynamics of the western spotted frog, Rana pretiosa pretiosa Baird & Girard, in Yellowstone Park, Wyoming. Ecol. Monogr. 30(3): 251-278.
- Tverdy, L. 2001. An analysis of the genotoxicity of mining effluent in toad tadpoles (Bufo boreas). Undergraduate Honors Thesis. Carroll College, Helena, MT. 21 p.
- Tverdy, L.M., N.J. Meis, C.G. Wicher, and D.G. Hokit. 2005. Comet assay used to detect genotoxic effects of mining sediments in Western Toad tadpoles (Bufo boreas). Herpetological Review 36(2):152-155.
- USDI Fish and Wildlife Service. 1994. Endangered and threatened wildlife and plants: 90 day finding and commencement of status review to petition listing of southern Rocky Mountain population of boreal toads as Endangered. Federal Register 59: 37439-37441.
- Van Kirk, R., L. Benjamin, and D. Patla. 2000. Riparian area assessment and amphibian status in the watersheds of the Greater Yellowstone Ecosystem. Greater Yellowstone Coalition, Bozeman, MT. 102 p.
- Vitt, L.J., J.P. Caldwell, and D.B. Shepard. 2005. Inventory of amphibians and reptiles in the Billings Field Office Region, Montana. Sam Noble Oklahoma Museum of Natural History and Department of Zoology, University of Oklahoma, Norman, OK. 33 pp.
- VTN Colorado, Inc. Decker Coal Company., 1975, Draft environmental impact assessment for the proposed North Extension of the West Decker Mine.
- Waldman, B. 1986. Chemical ecology of kin recognition in anuran amphibians. Proceedings of an International Conference on Chemical Signals in Vertebrates 4: 225-242.
- Walton, B.M., C.C. Peterson and A.F. Bennett. 1994. Is walking costly for anurans? The energetic cost of walking in the northern toad Bufo boreas halophilus. Journal of Experimental Biology 197: 165-178.
- Weisel, G.F. 1952. Animal names, anatomical terms, and some ethnozoology of the Flathead Indians. Journal of the Washington Academy of Sciences 42(11): 345-355.
- Wente, W., M.J. Adams, and C.A. Pearl. [In press]. Evidence of decline for Bufo boreas and Rana luteiventris in and around the norther Great Basin, western USA. Alytes 22.
- Werner, J.K. and T. Plummer. 1995a. Amphibian and reptile survey of the Flathead Indian Reservation 1993-1994. Salish Kootenai College, Pablo, MT. 55 pp.
- Werner, J.K. and T. Plummer. 1995b. Amphibian monitoring program on the Flathead Indian Reservation 1995. Salish Kootenai College, Pablo, MT. 46 p.
- Werner, J.K., B.A. Maxell, P. Hendricks and D.L. Flath. 2004. Amphibians and Reptiles of Montana. Mountain Press Publishing Company: Missoula, MT. 262 pp.
- Werner, J.K., T. Plummer, and J. Weaselhead. 1998b. The status of amphibians on the Flathead Reservation, Montana. Intermountain Journal of Sciences 4(3-4): 88.
- Western EcoTech, Helena, MT., 1999, Wetland delineation report for the Haskins Landing Proposed Wetland Mitigation Area. MWFE? June 2, 1999.
- Western Technology and Engineering, Inc. (WESTECH)., 1996, Wildlife Monitoring Absaloka Mine Area Annual Report, 1995. Montana SMP 85005. OSMP Montana 0007D. Febr. 23, 1996.
- Wicher, C.G. 2000. The effects of mining effluent on amphibian survivorship. Undergraduate Honors Thesis. Carroll College, Helena, MT. 18 p.
- Wiedmer, M. and R. P. Hodge. 1996. Geographic distribution: Bufo boreas. Hepretological Review 27:148.
- Wiedmer, M. and R.P. Hodge. 1996. Bufo boreas (western toad). Herpetological Review 27(3): 148.
- Woodward, B. and S. Mitchell. 1985. The distribution of Bufo boreas in New Mexico. Report to New Mexico Department of Game and Fish, Contract # 519-73-01. 25pp.
- Worrest, R.C. and D.J. Kimeldorf. 1976. Distortions in amphibian development induced by UV B enhancement 290-315 nanometers of simulated solar spectrum. Photochemistry and Photobiology 24: 377-382.
- Young, M.K. and D.A. Schmetterling. 2009. Age-related season variation in captures of stream-borne boreal toads (Bufo boreas boreas, Bufonidae) in western Montana. Copeia 2009:117-124.
- Zisook, R., K. Almond, and B. Sharpe. 1996. Amphibian survey of the Birch Creek drainage, Beaverhead County. Wildland Studies Project. San Francisco State University, San Francisco, CA. 9 p.
- Additional Sources of Information Related to "Amphibians"