Blue-black Grassquit
Volatinia jacarina
Adult blue-black grassquits are 10.2 cm (4.0 in) long and weigh 9.3 g (0.33 oz). They have a slender conical black bill. The male is glossy blue-black, with a black tail and wings; the white inner underwing is visible in flight or display. Female and immature birds have brown upperparts and dark-streaked buff underparts.
ID text from Wikipedia, CC BY-SA 4.0
Yellow-faced Grassquit
Tiaris olivaceus
It is a small bird with a conical bill, sharper than that of the related seedeaters. It is 10–10.7 cm (3.9–4.2 in) long and weighs about 8–10 g (0.28–0.35 oz), depending on subspecies. The adult male has an olive-green back, and its face and breast are black apart from a bright yellow throat, supercilia, and lower eyelid spot. The rest of the underparts are greyish olive. The beak and eyes are dark, while the legs are grey. The adult female is slightly smaller on average than the male. It is dull olive-green above and paler grey below, and may have some dark breast smudges. Voice: The yellow-faced grassquit has a weak buzzing trilled ttttt-tee call. The song is a varying series of high thin rapid trills. Given for a prolonged time, it is melodious, yet subdued, and often only heard from a short distance away.
ID text from Wikipedia, CC BY-SA 4.0
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