Bicknell's Thrush Fact Sheet
New York Status: Special Concern
Federal Status: Not Listed
©Jeff Nadler Photography
Previously thought to be a sub-species of the gray-cheeked thrush (Catharus minimus), the Bicknell's thrush was recognized as a distinct species in 1995. It is a small to medium sized thrush, measuring 6 to 7 ½ inches (15 - 19 cm) with olive to brown upper parts and gray or white under parts with a heavily spotted breast. Sexes are similar. When compared with the gray-cheeked thrush, the Bicknell's is smaller in size with more yellow on lower mandible and contrasting chestnut color on tail and wings. It prefers dense under story and thick tangles of brush or thicket.
The Bicknell's thrush is an elusive neotropical migrant that breeds in the high elevation forests of northeastern North America and winters in the Caribbean. Males arrive on the breeding grounds before females. Both sexes mate with multiple partners and each nest contains eggs fathered by different males. Males are not territorial but will compete for mating rights with females. Nest construction by the female occurs in a dense stand of young spruce or fir. The nest is a cup of twigs and mosses placed at the base of a group of branches against the trunk of a small tree. The clutch of 3 to 4 eggs is incubated by the female for 9 to 14 days. Young hatch almost bare but reach adult weight by the time they leave the nest 9 to 13 days post hatching. Both parents share in feeding the young. Diet consists of insects and other invertebrates found close to ground level. Forages by hopping along the forest floor and making short flights among the low branches of trees.
Distribution and Habitat
Bicknell's Thrush Range
The Bicknell's thrush is an eastern nearctic species with a very geographically limited breeding range that extends from the northern Gulf of the St. Lawrence and Nova Scotia, south through the mountains of New England and New York. It is a habitat specialist restricted to montane forests of balsam fir. In New York, the Bicknell's thrush breeds at high elevations in the Adirondack and Catskill mountains which represent the southern-most boundary of its breeding range. Because of its preference for stands of dense fir on ridgelines, the Bicknell's thrush is often associated with recently disturbed areas characterized by standing dead conifers and dense regrowth of balsam fir.
First discovered by Eugene Bicknell on Slide Mountain in the Catskills in 1881, this thrush is endemic to northeastern North America. The Bicknell's thrush is of high conservation priority because of its small population, limited breeding and wintering ranges, and vulnerability to deforestation in its winter habitat. Population data are difficult to gather because of the species' limited range and elusive breeding habits. Total population is thought to be less than 50,000 individuals. The significant geographic and habitat limitations of this species breeding range may make it vulnerable to the effects of climate change.
Distribution of Bicknell's Thrush in New York from
1st and 2nd NYS Breeding Bird Atlas Records
Management and Research Needs
Further research is needed to determine population characteristics as well as the distribution and extent of Bicknell's thrush breeding habitat in northeastern mountain forests. Little is known of Bicknell's thrush breeding and wintering ecology. Mercury pollution and acid deposition have contributed to the degradation of high elevation forests in the northeast since the 1960s and 1970s. Designation of the Catskills and Adirondack High Peaks Important Bird Areas by the Audubon Society offers some habitat protection.
Carleton, G. 1999. Birds of Essex County, New York. High Peaks Audubon Society, Elizabethtown, NY.
Rimmer, C. C., K. P. McFarland, W. G. Ellison, and J. E. Goetz. 2001. Bicknell's Thrush (Catharus bicknelli). In The Birds of North America, No. 592 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Peterson, J. M. C. 1988. Gray-cheeked Thrush. Catharus minimus. Pages 320-321 in Andrle, R. F. and J. R. Carroll, eds. The Atlas of Breeding Birds in New York State. Cornell Univ. Press, Ithaca, NY.
Rimmer, C. C. 2008. Bicknell's Thrush. Catharus bicknelli. Pages 442-443 in McGowan, K. J. and K. Corwin, eds. The Second Atlas of Breeding Birds in New York State. Cornell Univ. Press, Ithaca, NY.