Bicknell's thrush (Catharus bicknelli) is a medium-sized thrush, at 17.5 cm and 28 g. One of North America's rarest and most localized breeders, it inhabits coniferous mountain tops and disturbed habitats of the Northeast. While very similar in appearance and vocalization to the gray-cheeked thrush (Catharus minimus), the two species, with two completely different breeding ranges, differ slightly in their morphology and vocalizations.
Adults are olive-brown to brownish on the upperparts (head, nape, back) contrasting with chestnut-tinged tail. The contrast is, however, less evident in worn plumage. The underparts are off-white with gray on the flanks; the breast is off-white with buffy wash, showing dusky spots that becomes more diffuse toward the sides and the lower breast. They have pink legs, a faint grey eye ring, and gray cheeks. Two-thirds of the lower mandible is yellow colored, while the tip of the lower mandible and upper mandible is blackish.