Black-billed Thrush
Turdus ignobilis
The black-billed thrush is 18.5 to 24 cm (7.3 to 9.4 in) long and weighs 48 to 81 g (1.7 to 2.9 oz). The sexes have the same plumage. Adults of the nominate subspecies T. i. ignobilis have an olive-brown head and upperparts with a slightly darker face and an off-white throat with dark streaks. Their breast and flanks are a paler olive-brown and their belly and undertail coverts are whitish. They have a black iris, a black bill, and dark gray-brown to black legs and feet. Subspecies T. i. goodfellowi has warmer and darker olive-brown upperparts than the nominate. T. i. Voice: The black-billed thrush's song in Venezuela is "a rather slow caroling churre, churre, ee, TE-O-we, churre... and so on with pleasing, relaxed phrases; some individuals sing very repetitive phrases". It calls there are "a loud pfeea! or wEEa!". Similarly, in Peru it is described as "a pleasant and musical caroling, often with a particular phrase given twice".
ID text from Wikipedia, CC BY-SA 4.0
Creamy-bellied Thrush
Turdus amaurochalinus
The creamy-bellied thrush is 22 to 25 cm (8.7 to 9.8 in) long and weighs 52 to 73 g (1.8 to 2.6 oz). The sexes have the same plumage. Adults have a mostly olive-brown head with black lores and a brown-streaked white throat. Their upperparts, wings, and tail are the same olive-brown as the head. Their breast and flanks are usually grayish buff that becomes creamy white on the belly and undertail coverts. (Some individuals have pure gray instead of grayish buff underparts.) They have a dark iris, a yellowish bill when breeding and a darker one otherwise, and drab brown legs and feet. Voice: The creamy-bellied thrush's song is a "simple, little varied, yet musical series with short notes, like tjurre, wurr, tjeeh, and tjut-tjeé". Its calls include a "sharp pok", a "psiip in or before flight", and as a warning a "sharp kitten-like pchuo".
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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