Black-headed Siskin

The black-headed siskin is 10.2 to 11.5 cm (4.0 to 4.5 in) long and weighs about 10 to 14 g (0.35 to 0.49 oz). The species is sexually dimorphic. Adult males of the nominate subspecies S. n. notatus have a black head and upper breast. Their nape, back, and scapulars are yellowish olive-green with mostly hidden black spots in the middle of the feathers. Their rump and uppertail coverts are yellow. Their tail is mostly black with lemon yellow bases on the outermost pair of feathers. Voice: One description of the black-headed siskin's song is "a varied, rapid, jangling, twittering warble, often prolonged, with repetition of phrases and odd nasal and metallic notes thrown in". Another is a "rapid, liquid, tinkling, buzzy series of repeated elements lasting up to 15 sec.". Its calls include "a nasal teu...a drawn-out tseeeu, or djeein, a dry jeh-jeht, and a nasal ti-chie".