Black-crowned Night-Heron - Nycticorax nycticorax
The Black-crowned Night-Heron is a medium sized wading bird (length 58 to 66 cm) of stocky build, with a relatively large head, and fairly short neck and legs. Males and females are similar in plumage, with the males of slightly larger size. The adults are dominated by gray plumage, complete with black crown, black bill, and yellow to yellow-green legs. The eye, which start out as a grayish-olive at hatching, quickly turn to light yellow, bright yellow, orange, and finally to bright red by 2 to 3 years of age (Davis 1993). During the breeding season, adults also have long white occipital plumes (average of 2 to 3) extending from the distinctly black crown (Davis 1993, Sibley 2000). Juveniles have broad streaks of light brown-over-white on the breast and the wing coverts are covered in large, white spots. They lack the gray, black, and white plumage distinctive in the adults (Sibley 2000).
The common call of the Black-crowned Night-Heron includes a "Qua, Quak, Quark" or "Squawk," on the part of adults. An advertising call, identified as a hissing "Plup", is given from the nest, while the common call is given in flight or while perching (Davis 1993). The vocalization of the young varies as the birds age, from newly hatched to grown young, from a "Pip, Pip, Pip" to a "Chuck, Chuck-a-chuck, Chuck, Chuck" (Davis 1993).
The distinctive black crown and back, in addition to the gray body and yellow legs, make it hard to confuse this species with any other found in the state. The species to which it is most similar in appearance is the Yellow-crowned Night-Heron (Nyctanassa violacea), but this species lacks a black back, has a bold head pattern with a white cheek patch, and is very rare in Montana, having been recorded on only three occasions (Lenard et al. 2003). Young Black-crowned Night-Herons may sometimes be confused with American Bittern (Botaurus lentiginosus), but the American Bittern has a long, conspicuous mark on the side of the neck, bold stripes on the breast, dark flight feathers compared to the rest of the back, and lacks the large, pale spots on the underparts (Davis 1993, Sibley 2000).
Summary of Observations Submitted for Montana
Number of Observations:
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Map Help and Descriptions
(direct evidence "B")
(indirect evidence "b")
No evidence of Breeding
(regular observations "W")
(at least one obs. "w")
(Records associated with a range of dates are excluded from time charts)
The earliest records for Montana indicate arrival in April, with sightings throughout the summer months and extending into September, when most of the individuals begin their southerly movement (Johnsgard 1983, Lenard et al. 2003). In 2000, one individual was found in the Chester area that stayed until October (Lenard et al. 2003).
Although highly adaptable to a variety of habitats, the Black-crowed Night-Heron is likely to use shallow bulrush (Scirpus spp.) or cattail (Typha spp.) marshes, most often within a grassland landscape (Johnsgard 1983). In addition, they will also nest in cottonwoods, willows, or other wetland vegetation that allows them to nest over water or on islands that may afford them protection from mammalian predators (Davis 1993, Casey 2000). Most colonies are located in large wetland complexes, typically with a one-to-one ratio of open water and emergent vegetation (Davis 1993).
In general, Black-crowned Night-Herons are found in marshes, swamps, wooded streams, mangroves, shores of lakes, ponds, lagoons, in salt water, brackish, and freshwater areas. Foraging habitat is typically in the shallow, vegetated edges of these ponds, lakes, creeks, and marshes. This heron roosts by day in mangroves or swampy woodland. Eggs are laid in a platform nest in groves of trees near coastal marshes or on marine islands, swamps, marsh vegetation, clumps of grass on dry ground, orchards, and in many other locations. Nesting usually occurs in the same locality with other heron species.
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 (high, medium, or low) 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 2001, 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 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 associated as using 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 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.
High, medium, and low habitat quality was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species in the 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 assignments of habitat quality.
If you have any questions or comments on species associations with ecological systems, please contact Bryce Maxell at email@example.com
or (406) 444-3655.
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: http://mtnhp.org/requests/default.asp
) 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. 2001. The wild mammals of Montana. Special Publication No. 12. Lawrence, KS: The American Society of Mammalogists. 278 p.
- 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.
This heron feeds opportunistically on small animals, usually fishes, amphibians, and invertebrates obtained in shallow water, but will also prey on small mammals and young birds on land.
Aptly named, the large-eyed Black-crowned Night-Heron is crepuscular, hunting at dusk when it is generally too dark for other herons to catch prey. A gregarious species, the Black-crowned Night-Heron's earlier arrival to the breeding territories than other herons, in combination with its nocturnal hunting behavior, may lesson competition with other species within the nesting colonies (Davis 1993).
In Montana, breeding activities have been observed in May, June, and July. Preferring similar marsh habitat and possibly gaining protection from predators by nesting in a shared colony, Black-crowned Night-Herons often nest in close association with White-faced Ibis (Plegadis chihi) and Franklin's Gull (Larus pipixcan) (Davis 1993). Additionally, they have also been found to nest in colonies amidst Great Blue Herons (Casey 2000). With up to 30 known active nests in some years, Bowdoin National Wildlife Refuge has the largest recorded colony of breeding Black-crowned Night-Herons in the state (Lenard et al. 2003).
In general, the breeding season of this colonially nesting species varies geographically, occurring in spring to early summer in the northern portions of the range, and earlier further south. The nest sites are highly variable, from the ground to 160 feet high in trees (Davis 1993). The substrate may be anything from box elder or willows to cattails. Nests in trees may be located just about anywhere on the branches in relation to the trunk, and are composed of a platform of sticks, twigs, or reeds or whatever other material is nearby. Nests in cattails may be constructed on floating vegetation supported by adjacent stalks (summarized in Davis 1993). The average clutch of elliptical to subelliptical pale, greenish-blue eggs is usually three to five. The eggs are smooth and non-glossy, 53x37 mm in size (Baicich and Harrison 1997). The eggs are laid asynchronously and hatch generally in the same manner (Davis 1993). Incubation, performed by both sexes, lasts approximately 24 to 26 days. Young are tended by both sexes, and are capable of flight at about 42 days. The age of first breeding is usually at 2 to 3 years. This species nests in small to large colonies. See Custer et al. (1983) for data on certain Atlantic coast colonies.
Maintaining habitat integrity (appropriate water levels, and areas free from high levels of predation and harassment) at known nest locations is critical to their continued use (Casey 2000). No specific management actions have been identified for Black-crowned Night-Heron in Montana, but like many wetland dependent species, management of water resources that provide for natural seasonal water levels is essential for maintaining appropriate nesting sites (Davis 1993, Casey 2000).
- Additional ReferencesLegend: View WorldCat Record View Online Publication
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- American Ornithologists' Union. 1998. Check-list of North American birds. 7th edition. American Ornithologists' Union, Washington, D.C. 829 pp.
- Baicich, P. J., and C. J. O. Harrison. 1997. A guide to the nests, eggs and nestlings of North American birds. Second edition. Academic Press, New York.
- Burleigh, T.D. 1972. Birds of Idaho. The Caxton Printers, Ltd., Caldwell, ID. 467 pp.
- Casey, D. 2000. Partners in Flight Bird Conservation Plan Montana Version 1.0. Montana Partners in Flight. Kalispell, Montana.
- Casey, D. 2000. Partners in Flight Draft Bird Conservation Plan Montana. 281 pp.
- Custer, T. W., G. L. Hensler, and T. E. Kaiser. 1983. Clutch size, reproductive success, and organochlorine contaminants in Atlantic coast black-crowned night herons. Auk 100:699-710.
- Davis, Jr., William E. 1993. Black-crowned Night-heron (Nycticorax nycticorax). Species Account Number 074. The Birds of North America Online (A. Poole, Ed.). Ithaca, NY: Cornell Laboratory of Ornithology; Retrieved 3/25/2008 from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/
- Davis, W. E., Jr. 1993. Black-crowned Night-Heron (NYCTICORAX NYCTICORAX). In: The Birds of North America, No. 74 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington D.C.: The American Ornithologists Union. 20 pp.
- DeMauro, M. M. 1993. Colonial nesting bird responses to visitor use at Lake Renwick heron rookery, Illinois. Natural Areas Journal 13:4-9.
- Ehrlich, P., D. Dobkin, and D. Wheye. 1988. The Birder’s Handbook, A Field Guide to the Natural History of North American Birds. Simon and Schuster Inc. New York. 785 pp.
- Greedwood, R.J. 1981. Observations on Black-crowned Night Heron breeding success in a North Dakota marsh. Can Field-Nat. 95:465-467.
- Hancock, J. and J. Kushlan. 1984. The Herons Handbook. Croom Helm, Ltd., Kent.
- Herkert, J. R., editor. 1992. Endangered and threatened species of Illinois: status and distribution. Vol. 2: Animals. Illinois Endangered Species Protection Board. iv + 142 pp.
- Hoefler, J. E. 1979. Status and distribution of Black-crowned Night Herons in Wisconsin. Proceedings Colonial Waterbird Group 3:75-84.
- Johnsgard, P. A. 1986. Birds of the Rocky Mountains with particular reference to national parks in the Northern Rocky Mountain region. Colorado Associated University Press, Boulder. xi + 504 pp.
- Johnsgard, P.A. 1979. Birds of the Great Plains: breeding species and their distribution. Univ. Nebraska Press, Lincoln. 539 pp.
- Lenard, S., J. Carlson, J. Ellis, C. Jones, and C. Tilly. 2003. P. D. Skaar's Montana Bird Distribution, 6th Edition. Montana Audubon: Helena, MT, 144 pp.
- Lokemoen, J.T. 1979. The status of herons, egrets, and ibises in North Dakota. Prairie Nat. 11(4): 97-110.
- Montana Bird Distribution Online Database. 2001. Helena, Montana, USA. April-September 2003. http://nhp.nris.state.mt.us/mbd/.
- Montana Dept. of Fish, Wildlife and Parks. Region Four., 1996, Draft Environmental Analysis for Weed Management.
- Nickell, W. P. 1966. The nesting of the Black-crowned Night Heron and its associates. Jack-Pine Warbler 44:130-139.
- Palmer, R. S. 1962. Handbook of North American birds. Vol. 1. Loons through flamingos. Yale University Press, New Haven. 567 pp.
- Root, T. 1988. Atlas of Wintering North American Birds: An Analysis of Christmas Bird Count Data. The Univ. of Chicago Press, Chicago, IL. 312 pp.
- Sibley, D. A.. 2000. National Audubon Society The Sibley Guide to Birds. Alfred A. Knopf, Inc: New York, NY, 544 pp.
- Spendelow, J. A. and S. R. Patton. 1988. National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-1982. U.S. Fish and Wildlife Service, Biological Report 88(5). x + 326 pp.
- Tremblay, J., and L. N. Ellison. 1979. Effects of human disturbance on breeding of black-crowned night-herons. Auk 96:363-369.
- U.S. Forest Service. 1991. Forest and rangeland birds of the United States: Natural history and habitat use. U.S. Department of Agriculture, Forest Service Agricultural Handbook 688. 625 pages.
- Wolford, J.W. and D.A. Boag. 1971. Distribution and biology of Black-crowned Night Herons in Alberta. Can. Field-Nat. 85: 13-19.
- Wright, P.L. 1996. Status of rare birds in Montana, with comments on known hybrids. Northwestern Nat. 77(3):57-85.
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