Black-billed Nightingale-Thrush vs Slaty-backed Nightingale-Thrush

Black-billed Nightingale-Thrush

Catharus gracilirostris

Small21 gForest

The black-billed nightingale-thrush is about 15 cm (5.9 in) long and weighs about 20 g (0.71 oz) The sexes have the same plumage. Adults of the nominate subspecies have a slate-gray forecrown, an olive-brown crown, and a slate-gray face. Their upperparts, wings, and the upper side of their tail are olive-brown. Their throat is whitish, the middle of their lower belly light gray to whitish, and the rest of their underparts slate-gray with an olivaceous band across the breast. They have a dark brown iris, a black bill, and dark gray legs and feet. Voice: The black-billed nightingale-thrush has a variety of vocalizations. Its song is composed of up to about 18 phrases, each different than the preceding one, and typically alternating between higher and lower pitches. Males usually sing from within understory vegetation and only seldom much higher. During the breeding season males countersing.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Anthony Mora Aguilar · CC BY 4.0

Slaty-backed Nightingale-Thrush

Catharus fuscater

Small34 gForest

The slaty-backed nightingale-thrush is 17 to 18 cm (6.7 to 7.1 in) long. Specimens from Ecuador and Colombia weighed 30.5 to 38 g (1.1 to 1.3 oz). The sexes have the same plumage. Adults of the nominate subspecies C. f. fuscater have a dark slate gray head with a bright orange to yellowish orange eye-ring and a white to gray throat. Their upperparts are dark slate gray. Their underparts are mostly dark slate gray; the center of the breast and belly have varying amounts of white mixed in and sometimes a yellowish tint to the white. Voice: A lyric description of the slaty-backed nightingale-thrush's song is "a dreamy, mesmerizing series of low, flute like phrases...eer-lee or ur-eee-lee, phrases halting and hypnotic, as if disembodied from bird and floating eerily through the forest". Another description is "melodious and leisurely...a series of simple phrases, e.g, toh-toh-tee...tee-toh or tlee-to-tleedelee...to wee-tlee?".

ID text from Wikipedia, CC BY-SA 4.0

Recorded by Niels Krabbe · Song · Azuay: upper Yunguilla Valley, Ecuador · CC BY-SA 4.0

Photo: Fneskljvnl · CC BY 4.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Black-billed Nightingale-Thrush and Slaty-backed Nightingale-Thrush.