The Eurasian Siskin (Spinus spinus) is a small, yellow-green finch, the male crowned with a distinctive black cap, often seen in lively flocks hanging acrobatically upside down in alder and birch trees to pick at seeds. It measures 11–12 cm long with a wingspan of around 20–23 cm and weighs just 10–18 grams, with a slender, pointed bill. The male is yellow-green with a black crown and black chin, yellow-and-black wing bars and a yellow rump, while the female is paler and greyer-beige, more heavily streaked and lacking the black cap — the small size and yellow wing bars are good field marks for both.
The most common calls are a bright, slightly plaintive "tsi-ij" with a falling tone and a rising "tlu-i", while the song is a rapid, lively twitter often interrupted by a distinctive nasal, buzzing "tsjwee" — a flock high in the alder tops produces a constant, cheerful chatter. Breeding across most of Sweden, concentrated from Svealand northward in coniferous and mixed forest, with a population in the hundreds of thousands of pairs, the species is partly resident and partly a short-distance migrant, its movements driven strongly by seed availability; in winter Siskins gather in large, roaming flocks along alder-lined shores, and in some years irrupt southward in large numbers. It nests high in a conifer, often near the top of a spruce, building a small, well-hidden cup of twigs, lichen and feathers; the female lays 4–5 eggs and incubates about two weeks. Its diet is small seeds, chiefly from alder, birch and spruce, supplemented by insects in summer, and it readily visits garden feeders for niger and small sunflower seeds in autumn and winter.
Read about this species in Swedish →