The finches, which are considered the most highly developed of the birds, are widely diversified; they are classified into three groups: those with small, triangular bills, such as the canary, sparrow, bunting, towhee, junco, and those birds specifically named finch (e.g., chaffinch, bullfinch, and goldfinch); those with thick, rounded bills, as the grosbeak and cardinal; and the crossbills, rose-colored northern birds whose mandibles, as their name implies, cross over at the tips—an adaptation suited to their diet of conifer seeds.
The sparrows, genus Passer, which are field and hedge birds, are inconspicuously colored in dull grays and browns, but among the other, tree-perching finches, the male is often brightly plumaged (although the female is usually duller and sparrowlike). Most finches (except the meticulous goldfinch) build sloppy cup-shaped nests for their four to six speckled eggs.
Other species commonly called finches, especially many species kept as pets, are also found in other bird families. Estrildidae includes the grass, zebra, and parrot finches, waxbills, and munias, and Ploceidae includes the weaverbirds and whydahs.
Goldfinches, genus Astragalinus, named for the bright yellow markings of the male, are found in Europe and North America. The common American goldfinch, A. tristis (thistle bird, wild canary, or yellow bird), is a year-round resident everywhere on the North American continent except in the far north. There are several Western species. The British goldfinch is cinnamon brown with black and yellow wings and a red face. Goldfinches are cheerful, musical birds, although the so-called goldfinches commonly kept as cage birds are finchlike members of the weaverbird family. The European bullfinch, with blue-gray plumage above and terra-cotta below, is often caged; it can be taught to mimic tunes. The chaffinch, Fringilla coelebs, also popular in Europe as a cage bird, is similarly marked but with a chestnut back and wings and tail. In North America the sparrowlike eastern purple finch, Carpodacus purpureus (actually rose-brown), has been largely driven out by the house sparrow. There are several purple finches in the West, where the house finch, or linnet, is common. The rosy finches are western mountain dwellers. The house finch, Carpodacus mexicanus, known for its lilting song, was introduced to the eastern states from the West in the 1940s. In the Midwest the dickcissel, which winters in Central and South America, is valued as a destroyer of grasshoppers. Several longspurs, genus Centrophanes, are found from the Great Plains northward; the Lapland longspur is a European finch that ranges to the NE United States. The redpolls, genus Aegiothus, are northern finches that winter in the N United States; with the pine siskins, goldfinches, and various other seedeaters they wander around the country in small flocks, often congregating at feeding stations. The grassquits, genus Phonipara, are native to the Bahamas and Cuba; the brambling, or mountain, finch is a N Eurasian bird that winters in the British Isles.
Finches are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Fringillidae.
Finches are passerine birds, often seed-eating, found chiefly in the northern hemisphere and Africa. One subfamily is endemic to the Neotropics. The family scientific name Fringillidae comes from the Latin word "fringilla", meaning chaffinch, a member of this family that is common in Europe. The taxonomic structure of the true finch family, Fringillidae, is somewhat disputed, with some including the Hawaiian honeycreepers as another subfamily (Drepanidinae) and/or uniting the cardueline and fringilline finches as tribes (Carduelini and Fringillini) in one subfamily; the euphonious finches were thought to be tanagers due to general similarity in appearance and mode of life until their real affinities were realized; the buntings and American sparrows were formerly considered another subfamily (Emberizinae). Przewalski's "Rosefinch" (Urocynchramus pylzowi) is now classified as a distinct, monotypic family with no particularly close relatives (Groth 2000).
"Classic" or true finches are small to moderately large and have strong, stubby beaks, which in some species can be quite large. All have 12 tail feathers and 9 primaries. They have a bouncing flight, alternating bouts of flapping with gliding on closed wings, and most sing well. Their nests are basket-shaped and built in trees. The true finches range in size from the Andean Siskin (Carduelis spinescens), at 9.5 cm (3.8 inches) and 8.4 g., to the Collared Grosbeak (Mycerobas affinis), at nearly 23 cm (9 inches) and 79 g. (2.8 oz).
There are many birds in other families which are often called finches. These include many species in the very similar-looking Estrildids or waxbill family, which occur in the Old World tropics and Australia. Several groups of the Emberizidae family (buntings and American sparrows) are also named as finches, as are Darwin's finches of the Galapagos islands, which provided evidence of natural selection.