The finches form a large family and some authorities split them in two, the majority in the Carduelidae, with the Chaffinch and Brambling being considered sufficiently distinct to merit a family of their own (along with the Blue Chaffinch, found only on the Canary Islands). They are more catholic in their choice of habitat and diet than the true finches. The true finches are usually birds of woodland which specialise in eating seeds, each species having a distinctive bill morphology adapated for a particular range of weed or tree seeds. These range from the delicate bill of the Siskin adapted to removing seeds from alder and birch cones, through the unique crossed-bill of the Crossbill adapted for extracting seeds from pine and spruce cones, to the massive bill of the Hawfinch which can crack cherry stones. The Linnet is one of the few birds that feeds its young entirely on seeds.
Finches occur throughout the world (except Australia) and many species are semi-nomadic, particularly in the non-breeding season, following the seed crop. One species, the Scottish Crossbill, is thought to be restricted to Scottish pinewoods and would thus be the only bird species restricted in its distribution to Britain (and one of the few restricted to Europe), however its taxonomic status is uncertain and it may represent a subspecies of the Common Crossbill. While the three fringilline finches are territorial in summer, the cardueline finches are much less so and many nest in loose colonies.
The exotic finches often kept as cagebirds, such as the Zebra Finch, and which occasionally escape, are not in fact finches but waxbills (family Estrildidae), distinguished by their colourful, small conical bills.