The yellow-bellied siskin (''Spinus xanthogastrus'') is a small

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

in the

finch The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches generally have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where the ...

family Fringillidae. It breeds from

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

south to southern

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

, central

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

and the highlands of northwestern

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Description

The yellow-bellied siskin is a small bird, 10.5 cm in length and weighing 12 g. The male is entirely black except for a bright yellow belly, tail sides and wing patches. The female is dark olive green above and has pale yellow underparts which become brighter on the belly. She has a blackish tail and wings and also has bright yellow primary wing patches and tail sides. Young birds resemble the female, but have dusky fringes to the upperpart feathers and smaller yellow wing and tail patches. The song of this bird is a pleasant chattering twitter, and the call is a sharp '. The subspecies ''S. x. stejnegeri'', which occurs from extreme southeastern

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

to central Bolivia, is larger and longer-billed than the nominate subspecies ''S. x. xanthogastrus''. Males have larger yellow wing patches and more extensive black on the flanks. Females of this subspecies are darker olive above than the northern birds. The yellow-bellied siskin is more of a woodland bird than the superficially similar

lesser goldfinch The lesser goldfinch (''Spinus psaltria'') is a small finch in the genus '' Spinus'' native to the Americas. As is the case for most species in the genus ''Spinus'', lesser goldfinch males have a black forehead, which females lack. Males in this ...

(''Spinus psaltria'') and the latter species is paler and has a white wing patch and a more musical song.

Behaviour and ecology

The yellow-bellied siskin breeds in mountain

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

forests at altitudes between 800–3,000 m. The nest is a shallow cup of rootlets, bark and

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s 2.4–3.7 m high in the dense foliage of a small tree in a clearing. The two or three green-tinged white eggs are laid in April or May and incubated by the female. Although not migratory, this species wanders within its range when not breeding. The yellow-bellied siskin has been relentlessly persecuted for the cage-bird trade in some areas, such as central

. Where it remains common, in remote or protected areas, flocks of up to 30 birds forage in the canopy for small

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s and oak flowers, or descend to clearings for seeds. The males may sing socially.

References

Other sources

* Clement, Harris and Davis, ''Finches and Sparrows'' * Hilty, '' Birds of Venezuela'', * Stiles and Skutch, ''A guide to the birds of Costa Rica'' {{Taxonbar, from=Q27075869 Spinus (genus) Birds of the Talamancan montane forests Birds of the Northern Andes Birds described in 1855 Taxa named by Bernard du Bus de Gisignies