New York Natural Heritage Program
Bicknell's Thrush
Catharus bicknelli (Ridgway, 1882)
Birds

General Description [-]
This is a medium-sized thrush (6-7"; 1 oz.), but smaller and more slender than most Catharus thrushes. The upper parts are a warm brownish color and the breast is heavily spotted with brown over a white belly. A reddish tinge is present on the wings and tail.

Identifying Characteristics [-]
The Bicknell's Thrush song consists of two introductory plucking notes (only audible at 10-12 meters) hurriedly followed by 2-4 high-pitched vibrant, ringing phrases that slur downward: rendered as "chook-chook, wee-o, wee-o, wee-o-ti-t-ter-ee" (Rimmer et al. 2001). Nests (12x12 cm) are cup-shaped and bulky, built primarily of twigs and moss, with an interior layer of decayed vegetation. The small (22x17 mm) eggs are subelliptical and bluish-green with light brown speckling (Rimmer et al. 2001).

Characters Most Useful for Identification [-]
Subtle, but clear differences in song distinguish Bicknell's from other Catharus thrushes.

Behavior [-]
This thrush species has a male-skewed sex ratio and is considered to be polygynandrous. Single broods are sired by multiple males, and multiple males also bring food to a single nest (Goetz at al. 2003). This breeding system is assumed to be an adaptation to harsh montane conditions (Strong et al. 2004) where Bicknell's expend large amounts of energy for thermoregulation (Holmes and Sawyer 1975). Individuals are secretive and elusive, staying hidden among dense undergrowth and seldom coming out into the open. Males perform an evening flight song (Evans 1994).

Diet [-]
Bicknell's Thrushes feed on insects and other arthropods, especially beetles and ants. The species is considered predominantly a ground forager, but sometimes fly-catches from an exposed perch (Rimmer et al. 2001).
Bicknell's Thrush Images
click to enlarge
The Best Time to See
This is one of the last migrants to return to the breeding grounds in the spring (Ouellet 1996). Courtship activities begin shortly after arrival in mid May, nest-building begins by early June, eggs are laid by mid June, eggs hatch in late June, and the young fledge during July (Rimmer et al. 2001).
J F M A M J J A S O N D
Present Breeding
The time of year you would expect to find Bicknell's Thrush present (blue shading) and breeding (orange shading) in New York.
Similar Species
  • Swainson's Thrush (Catharus ustulatus)
    Swainson's buffy facial pattern and distinct eye-ring are pronounced.
  • Gray-Cheeked Thrush (Catharus minimus)
    These two species are very similar and the Bicknell's was formerly considered a subspecies of the Gray-cheeked. However they are wholly allopatric during the breeding season and the Gray-cheeked is somewhat larger, its upper parts are more grayish- brown.
  • Veery (Catharus fuscescens)
    Veerys are more richly and uniformly reddish-brown above and less heavily spotted on the breast.