Eurasian Siskin - Description

Description

The Siskin is a small, short-tailed bird, 11–12.5 centimetres (4.3–4.9 in) in length with a wingspan that ranges from 20–23 centimetres (7.9–9.1 in). It weighs between 10–18 grams (0.35–0.63 oz).

The bird's appearance shows sexual dimorphism. The male has a greyish green back; yellow rump; the sides of the tail are yellow and the end is black; the wings are black with a distinctive yellow wing stripe; its breast is yellowish becoming whiter and striped towards the cloaca; it has a black bib (or chin patch) and on its head it has two yellow auriculas and a black cap. The amount of black on the bib is very variable between males and the size of the bib has been related to dominance within a flock. The plumage of the female is more olive-coloured than the male. The cap and the auriculas are greenish with a white bib and a rump that is a slightly striped whitish yellow. The young have a similar colouration to the females, with drab colours and a more subdued plumage.

The shape of the Siskin's beak is determined by its feeding habits. It is strong although it is also slender in order to pick up the seeds on which they feed. The legs and feet are dark brown and the eyes are black.

It has a rapid and bounding flight pattern that is similar to other finches.

The Siskin is easy to recognize, but in some instances it can be confused with other finches such as the Citril Finch, the Greenfinch or the European Serin. Whereas the European Siskin, in many plumages, is a bright bird, the Pine Siskin in its typical morph is a drab by comparison. Adult male European Siskins are bright green and yellow with a black cap, and an unstreaked throat and breast; the Pine Siskin does not have a corresponding bright plumage. Adult female European Siskins also usually have green and yellow plumage tones: for example, yellow in the supercilium and on the sides of the breast, green tones in the mantle and yellow in the rump. Adult Pine Siskins of the typical morph do not have green and yellow tones, although juveniles can have a yellowish-buff wash on their underparts and buff-toned wingbars, for a short period prior to their autumn migration. The ground colour of the underparts of European Siskin is normally pure white, whereas on Pine Siskin it is usually a dirtier colour. In female and juvenile European Siskin, the centre of the belly and lower breast are often largely or entirely unstreaked, whereas in most Pine Siskins the streaking extends across the whole of the underparts. The wingbars of European Siskin are broad and yellow (with the tips white) whereas they are normally narrower and buffish-white in Pine Siskin, contrasting with the bright yellow flash at the base of the primaries. Pine Siskins have a longer bill, usually with a straight culmen, compare with a short bill in European Siskin, with a decurved culmen. There is a green morph of Pine Siskin which is closer in appearance to European Siskin; these birds make up only 1% of the population. These are closer in appearance to female European Siskin, but differ in that they have a yellow-wash on the undertail-coverts (white on European Siskin), no yellow in the supercilium, reduced underparts streaking, and much yellow at the base of the tail and remiges; there may also be a difference in the extent of yellow in the underparts but this needs further study.