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Bicknell's Thrush | Catharus bicknelli
Bicknells dwerglijster | Zorzal de Bicknell
Bicknell's Thrush is one of the few North American songbirds that winters almost exclusively in the Caribbean. It breeds in stunted balsam fir forest on mountain tops in the north-eastern United States and south-eastern Canada; an estimated 90% of birds winter on Hispaniola, mainly in the Dominican Republic. Until 1995 it was treated as a subspecies of Grey-cheeked Thrush.
Voice
In winter mainly a falling, nasal beer or pheu and a soft chook. It rarely sings on the wintering grounds. The song on the breeding grounds is a high, fluted, spiralling series that rises at the end.
Recording: Stanislas Wroza — CC BY-NC-SA 4.0 · shortened to the first 60 s, mono · xeno-canto
Identification
16–17 cm, the smallest Catharus thrush in the region. Upperparts greyish olive-brown, tail and primaries tinged warmer chestnut. Cheeks greyish, eye-ring faint grey. The breast is washed buff with blackish triangular spots, the belly white and the flanks grey. A fairly large part of the base of the lower mandible is yellow. The sexes are alike.
Confusion species
Grey-cheeked Thrush Catharus minimus is slightly larger and colder grey-brown, without a warm tone in tail and wing, and shows less yellow on the lower mandible; in the field the two often cannot be separated with certainty. A wintering bird in montane forest in the Greater Antilles is almost always a Bicknell's, since Grey-cheeked winters in South America. Swainson's Thrush Catharus ustulatus has buff spectacles.
Habitat
In winter in humid montane rainforest and cloud forest with broadleaf trees, from about 400 m to above 2000 m, favouring higher, undisturbed forest. Males more often occupy old forest at higher elevations, females and young birds more often lower or disturbed forest. It forages on or near the ground for insects and eats fruit.
Where the bird is most at home, classified by the vegetation types of the Caribbean.
Range and movements
A winter visitor to Hispaniola: in the Dominican Republic in the Cordillera Central, Sierra de Bahoruco, Sierra de Neiba and Cordillera Septentrional, in Haiti in the Massif de la Hotte and Massif de la Selle. Smaller numbers in Puerto Rico (including El Yunque and Maricao) and in the mountains of eastern Cuba (Sierra Maestra and Nipe-Sagua-Baracoa); rare on Jamaica. A passage migrant in the Bahamas, where it is rarely recorded. It breeds on mountains in New York, New England, Quebec and the Canadian Maritimes.
- Winter visitor (c. Apr–Sep)
- dark = core range, pale = thinly spread
How and when to look
In winter best early in the morning in cloud forest in the Sierra de Bahoruco or the Cordillera Central of the Dominican Republic, where the birds forage on the ground along trails. The call is often the first sign. In winter identification rests mainly on place and habitat.
Conservation status
Vulnerable. The world population is small and declining. The greatest threat is deforestation on the Hispaniolan wintering grounds, especially in Haiti; on the breeding grounds climate change and acid rain play a part.
Scientific name
Catharus bicknelli | (Ridgway, 1882)
Ridgway described the species in 1882 as Hylocichla aliciae bicknelli; because it was later moved to another genus, the author and year stand in brackets. The genus Catharus was introduced in 1850 by Bonaparte. Catharus is from Ancient Greek katharos 'pure, clean', a name given for the clean plumage of the orange-billed nightingale-thrush. bicknelli honours the American amateur ornithologist and botanist Eugene Pintard Bicknell (1859–1925), who discovered the bird in the Catskills in 1881. The specimen the first description was based on came from Slide Mountain, Catskills, New York, USA.