Spinus tristis
A small, vibrant yellow finch and one of the strictest vegetarians in the bird world. Specializes in consuming seeds from composite flowers, particularly thistles, sunflowers, and coneflowers. Named for its bright lemon-yellow breeding plumage and characteristic undulating flight.
Seasonal Activity
Diet
Seeds of thistles, sunflowers, coneflowers, dandelions, ragweed, and other composites; tree buds, maple sap, and occasional insects fed to nestlings
Lifecycle
Short-distance migrant. Breeding begins unusually late (late July-August), timed to coincide with peak seed availability from composite flowers. Nests are tightly woven cups of plant fibres and spider silk, lined with thistle or milkweed down. Clutch is 4-6 bluish-white eggs, incubated by the female for 12-14 days. Chicks fledge at 11-15 days. One brood per year. Both sexes undergo complete spring and autumn molts — the only cardueline finch to do so. Winter flocks are gregarious and nomadic.
Ecology
Native Habitats
Details
Description
The American Goldfinch (Spinus tristis) is a small finch, 11-14 cm long with a wingspan of 19-22 cm and weighing 11-20 g. It exhibits striking seasonal sexual dichromatism: breeding males are brilliant lemon yellow with a jet-black cap, black wings with white bars, and a white rump visible in flight. Females and winter birds are dull olive-brown above, paler below, with a pale yellow bib and dark wings. The conical bill is pink for most of the year and turns bright orange during the spring molt.
The only finch in its subfamily to undergo a complete molt twice annually, the goldfinch's vibrant breeding plumage is produced by carotenoid pigments from its seed-based diet. It is the state bird of Iowa, New Jersey, and Washington. The species is globally Secure, with an estimated 42-47 million mature individuals, though recent surveys indicate population declines.
Lifecycle
Breeding begins remarkably late for a North American songbird — late July through August — timed to the peak availability of thistle and composite seeds, which form the bulk of both adult and nestling diet. Courtship involves aerial displays and singing by males. Nests are constructed by females in the branches of deciduous shrubs or trees, 1-10 m above ground. The nest is an exceptionally tightly woven cup of plant fibres, bark, and spider silk, so dense it can hold water.
Clutches consist of 4-6 bluish-white eggs, incubated solely by the female for 12-14 days. The male feeds the female on the nest during incubation. Chicks are altricial at hatching and are fed regurgitated seeds. They fledge at 11-15 days and remain dependent on the male for up to three additional weeks. Most pairs raise only one brood per year.
Winter flocks are gregarious and nomadic, moving in response to seed availability. The species is a short-distance migrant, with Ontario birds moving south as temperatures approach freezing. Flocks exhibit an erratic, undulating flight pattern with distinctive "per-chic-o-ree" calls given during the flapping phase of each undulation.
Ecology
The American Goldfinch is one of the strictest vegetarians among birds, with seeds comprising the overwhelming majority of its diet year-round. Favoured food plants include thistles (Cirsium, Carduus), sunflowers (Helianthus), dandelions (Taraxacum), ragweed (Ambrosia), and various grasses. The bird uses its feet to grip seedheads while extracting seeds with its conical beak — a dexterity that allows it to access food sources unavailable to competitors.
Insects form a minor dietary component, primarily fed to nestlings for protein. The species' late breeding season helps it avoid Brown-headed Cowbird parasitism, which is rare and unsuccessful in goldfinch nests due to the seed-based diet.
Habitat
Prefers open country with abundant seed-producing plants: weedy fields, meadows, floodplains, roadsides, orchards, and gardens. Also found in open deciduous and riparian woodlands, particularly areas of secondary growth. In Ontario, the species breeds throughout the province south of the boreal shield, frequenting both agricultural landscapes and natural areas including Tallgrass Prairie remnants and Oak Savanna edges. Human land use has generally benefited the species by creating open, weedy habitats and by providing winter bird feeders.