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Black-and-white Warbler - Mniotilta varia

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S4B
(see State Rank Reason below)


Agency Status
USFWS: MBTA
USFS:
BLM:
PIF:



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Listen to an Audio Sample
Copyright by Borror Laboratory of Bioacoustics, Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, all rights reserved.
State Rank Reason (see State Rank above)
Species is somewhat common within appropriate habitat but faces several threats and appears to be declining.
Black-and-white Warbler (Mniotilta varia) Conservation Status Summary
State Rank: S4B
Review Date = 12/26/2023
How we calculate Conservation Status
Rarity: VeryUncommonVeryCommon Threats: HighlyThreatenedUnthreatened Trends: RapidlyDecliningDecliningStableIncreasing Rank: S1 S2 S3 S4 S5 CriticallyImperiledSecure

See the complete Conservation Status Report
 
General Description
Distinctly striped in black-and white plumage with a slightly decurved bill for bark foraging, the Black-and-white Warbler moves vertically along tree trunks, exhibiting characteristics generally attributed to nuthatches. The adult body length ranges from 11 to 13 cm, with an average wingspan of 21 cm. Body mass ranges from 8.8 to 15.2 grams, and bill length from 10.0 to 13.7 mm. The female is the smaller of the two sexes. Males, exhibiting darker, more contrasted markings than females in both breeding and non-breeding plumages, are defined by conspicuous black and white coloration. In breeding plumage, the male crown has a broad white median stripe, black sides, and a broad white superciliary stripe that extends to the nape. The lores and ear coverts are black, while the submustachial stripe is white above a black throat with black and white streaked sides of the neck. A white eye-ring contrasts with black ear coverts. The upper and underparts are streaked with black and white, the underparts being the more distinct and boldly marked. The wings are black with two evident wing bars. The feathers of this warbler's truncate tail are dull black marked with white, revealing white tail spots. The female's breeding plumage is similar to the males, but with pale gray lores and ear coverts and less contrasting black and white markings overall. A narrow, black eye stripe, white throat, and a less defined streaking on the back also distinguish the female from the male. Additionally, the female's tail spots are less distinct and a faint buff wash on the flanks and sides of the throat is generally present (Kricher 1995). The eyes have a brown iris. The feet in the juveniles are a pinkish-buff, becoming darker to black with age.

The vocalization of the Black-and-white Warbler is described as a thin, high-pitched two syllable squeaky "weesee, weesee, weesee," or "squeaky, squeaky, squeaky," repeated upwards of ten times (Kricher 1995). One of the highest pitched of the wood warblers, the song of the Black-and-white Warbler is described as resembling the sound of a wet rag wiped repeatedly across glass (Bent 1953, Kricher 1995). During breeding, a variation of the primary song is of a longer, faster, and more varied pitch (Bent 1953). Although varied, the call note of this species can be described as a sharp "chip," "pit," or sharp rattling "stick" (Terres 1980, Sibley 2000).

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

Diagnostic Characteristics
The Black-and-white Warbler is distinguished from similar warbler species by its distinctive black and white plumage and its nuthatch-like foraging behavior. Few other wood warblers forage in this manner, and those that do are not black and white in coloration. The two other black and white warblers in Montana, the Blackpoll Warbler and the Black-throated Gray Warbler, are noticeably different in plumage. The Blackpoll Warbler has an un-striped black crown and white cheek and throat, while the Black-throated Gray Warbler has a bright yellow spot in front of each eye, a solid black (or black and gray) un-striped head, and a mostly gray, un-striped back (Kricher 1995, Sibley 2000). Neither of these two species possess a decurved bill (Sibley 2000).

Species Range
Montana Range Range Descriptions

All Ranges
Summer
Migratory
(Click legend blocks to view individual ranges)

Western Hemisphere Range

 


Observations in Montana Natural Heritage Program Database
Number of Observations: 525

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

SUMMER (Feb 16 - Dec 14)
Direct Evidence of Breeding

Indirect Evidence of Breeding

No Evidence of Breeding

WINTER (Dec 15 - Feb 15)
Regularly Observed

Not Regularly Observed


 

(Observations spanning multiple months or years are excluded from time charts)



Migration
Less dependent upon flying insects, the Black-and-white Warbler generally arrives earlier in the spring and stays later in the fall than other warbler species (Johnsgard 1986). Birds have been recorded in Montana and southern Alberta from early May through early September. May is the earliest month recorded for Black-and-white Warbler observations in Montana. The majority of the latest season records are for August, although one record just south of Ninepipe National Wildlife Refuge indicates an individual present in October (Montana Bird Distribution Committee 2012).

Habitat
Information on habitat use in Montana is limited. Existing records indicate observations in riparian habitat and woody draws, those of mixed deciduous and ponderosa pine (Pinus ponderosa), in the eastern part if the state (Skaar unpublished data). One observation record indicates a female feeding on Douglas-fir (Pseudotsuga menziesii) northeast of Helena, while numerous records exist for the deciduous habitat in the town park in Westby, as well as that of several backyards, specifically in the northeast portion of the state (Montana Bird Distribution Committee 2012).

In general, the Black-and-white Warbler inhabits young, medium-aged and mature deciduous and mixed forests during the breeding season (Bushman and Therres 1988, Kricher 1995). Studies of habitat selection have yielded conflicting results that appear to be due to geography, as well as variations in forest type and stand age. In the southern part of its range, this species appears to be most closely associated with relatively closed-canopied forests with low shrub density (Conner et al. 1983, Crawford et al. 1981, Noon et al. 1980, Wilson et al. 1995). In aspen forests in Alberta, however, stands with high shrub density were avoided (Westworth and Telfer 1993). Black-and-white Warblers were associated with high tree density and high canopy volume (indicative of mid- to late-successional forests) in mixed forests of central Ontario (Clark et al. 1983). The Black-and-white Warbler typically nests on the ground, often adjacent to a tree, shrub, rock, stump or log, under a shrub or dead branches, or, more rarely, atop stumps (Bent 1953, Kricher 1995).

A wide variety of habitats are used during the non-breeding season, from early successional disturbed areas to mature forests (Kricher 1995). Caribbean habitats utilized include coastal forest, dry interior forest, wet forest, forest edge, pine woods, riparian areas, wetlands, urban habitats that provide plant cover, and some open areas (Arendt 1992). Cacao, citrus, mango, shade coffee, and pine plantations in Puerto Rico, Jamaica, and Costa Rica are also selected (Robbins et al. 1992). Even though it showed a preference for undisturbed habitats, particularly forest, this species is considered a habitat generalist in western Mexico (Hutto 1992). Primary forest is preferred to other habitat types in the Yucatan Peninsula, Mexico (Greenberg 1992, Lynch 1989) and in Veracruz, Mexico (Rappole et al. 1992). In the Virgin Islands, they exhibited a preference for moist forest (90.5% of detections) over other habitat types (Askins et al. 1992).

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:
    1. 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);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
    4. 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.

    Literature Cited
    • 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.

Food Habits
Foraging principally by creeping along tree trunk and branches, Black-and-white Warblers also foliage glean (Bent 1953, Kricher 1995). The main food items are chiefly insects, including beetles (Coleoptera), caterpillars and moths (Lepidoptera), ants and other Hymenoptera, flies (Diptera), and bugs (Hemiptera), and may include spiders (Arachnida) and harvestmen (Phalangida) (Bent 1953). Lepidopteran larvae are important prey during spring migration (Graber and Graber 1983). The remains of a small lizard were found in the stomach of one Texas specimen, indicating further variety in their diet (Oberholser 1974).

Ecology
Little information exists for this species in Montana.

In quaking aspen (Populus tremuloides) forest in Alberta, male pairing success was lower in forest fragments (56%) than in continuous forest (80%) but due to small sample sizes, the difference was not statistically significant (Sodhi and Paszkowski 1997). The Black-and-white Warbler occurs commonly in small, mixed species flocks of warblers in the Virgin Islands in winter where density in moist forest was less than 1 per hectare on St. Thomas and 1 to 2 per hectare on St. John (Ewert and Askins 1991). Conflicting reports of winter territoriality exist (Faaborg and Arendt 1984, Morton 1980).

Site fidelity is exhibited on the wintering grounds in Puerto Rico where 22% of banded birds were recaptured at the study site. The average time between banding and recapture was 1.9 years; the longest interval was 4 years (Faaborg and Arendt 1984). Twenty percent of birds captured in Cuba were birds banded there the previous year (Gonzalez-Alonso et al. 1992).

The average annual adult survivorship is estimated to be 71%, with the oldest known individual aged at 11 years, 3 months old (Klimkiewicz et al. 1983, Kricher 1995).

Known parasites on Black-and-white Warblers include blood parasites (Haemoproteus spp. and Leucocytozoon spp.), feather mites, a louse species (Myrsidea incerta), and one fly species (Ornithoica confluens) (Bent 1953, Kricher 1995). Bent (1953) indicates maggots destroyed a nestful of young.

Reproductive Characteristics
One record of direct evidence of breeding was recorded in Valley County, but details of the nesting event appear lost (Skaar unpublished data, Montana Bird Distribution Committee 2012). Additional observations that indicate behavior suggesting breeding have been recorded in Roosevelt, Sheridan, Daniels, Dawson, Richland, Rosebud, and Carter counties (Skaar unpublished data, Montana Bird Distribution Committee 2012), but no details on these records are documented. No other information is available on the reproductive habits of the Black-and-white Warbler in Montana.

In general, breeding begins as early as mid-April at southern latitudes and as late as late July at northern latitudes. The female builds the cup-shaped nest of grasses, dry leaves, strips of inner bark, and pine needles lined with finer grasses, rootlets, hair or mosses (Terres 1980, Baicich and Harrison 1997). Clutch size is usually five, ranging from 4 to 6 eggs. Eggs are laid daily until the clutch is complete. Eggs are short, sub elliptical, and range in color from white or cream-white, sometimes pale bluish or greenish-white, with finely speckled pigments of brown, and occasionally lavender and pale lilac, encircling the larger end. Dimensions average 15.50 to 18.46 mm by 13.02 to 13.64 mm with average weights of 0.076 gram (Kricher 1995).

Incubation, which requires 10 to 12 days, begins when the penultimate or last egg is laid and is conducted by the female only. When threatened, females may perform a distraction display described as the "rodent run," for its hunched posture and tail drag (Kricher 1995). The young are fed by both parents and leave the nest at 8 to 12 days post hatching. This species is single brooded, though double broods are suspected (Kricher 1995). In Arkansas, 73.7% of 19 nests were successful (fledged at least one young) (Martin 1993). Age at sexual maturity is unknown (Kricher 1995).

Management
No management activities in Montana specific to the Black-and-white Warbler are documented.

Stewardship Responsibility

Based on the Montana Natural Heritage Program's latest predicted habitat suitability model

Total species' range in Montana 164,546 km2 (43% of Montana)
Area predicted to have
some level of suitable habitat
72,176 km2 (19% of Montana)

Stewardship responsibility for the predicted area of suitable habitat can be broken down as follows

  Total Suitable Optimal Suitability Moderate Suitability Low Suitability
Federal 15% <1% 1% 14%
State 6% <1% <1% 6%
Local <1% <1% <1% <1%
Conservation Lands/Easements 1% <1% <1% 1%
Private/Tribal/Unknown 77% 1% 5% 71%

See the Habitat Suitability for Biodiversity task in Map Viewer for a more detailed look at stewardship responsibilities within a variety of local jurisdictions.


References
  •  Literature Cited Above
  •  Additional References
  •  Web Search Engines for Articles on "Black-and-white Warbler"
  •  Additional Sources of Information Related to "Birds"
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Citation for data on this website:
Black-and-white Warbler — Mniotilta varia.  Montana Field Guide.  .  Retrieved on , from