Olive-backed Euphonia
Euphonia gouldi
The olive-backed euphonia is 9 to 10 cm (3.5 to 3.9 in) long and weighs about 11 to 16 g (0.39 to 0.56 oz). It is a small euphonia with a thick stubby bill. The species is sexually dimorphic. Adult males of the nominate subspecies have a yellow forehead; the patch extends to the rear of the eye and sometimes has light black flecks. The rest of their crown, and their nape, upperparts, and tail are olive-green. All of them except the uppertail coverts have a bluish gray gloss. Voice: The olive-backed euphonia's song is "a rapid jumble of chatters, buzzes, and harsh whistles". Its calls "include a chi'chi'chi'cheet and a liquid tsip'please-seeee'up!. Another description of its song is "a rambling medley of whistles, chatters and staccato notes, some dry and chaffy, some musical" that may continue for a long time.
ID text from Wikipedia, CC BY-SA 4.0
Yellow-crowned Euphonia
Euphonia luteicapilla
The yellow-crowned euphonia is about 9 to 10 cm (3.5 to 3.9 in) long and weighs 11.4 to 14.5 g (0.40 to 0.51 oz). It has a short stubby bill. The species is sexually dimorphic. Adult males have a large yellow forecrown and crown; the color extends well past the eye. The rest of their head, nape, and throat are glossy blue-black. Their upperparts, wings, and tail are also glossy blue-black. Their breast, belly, and undertail coverts are bright yellow. Adult females have an olive head, upperparts, wings, and tail with a yellowish tinge on the forehead. Voice: The yellow-crowned euphonia sings "a short, dry sputtering series of notes, e.g. pit ditrééa-twiddledee bee bee" that has also been described as "a short wiry chut-tsip ts’tsew tsiuweer". Its call is "a series of 2–3 clear high whistled notes that may be given at varying speed, ee-bee-bee" or given as a longer series "beebee, peepeepee". It also makes "tsit notes" as a contact and flight call.
ID text from Wikipedia, CC BY-SA 4.0
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