The finch family of birds, scientifically known as the Fringillidae, are a group of passerine birds, meaning seeds are a primary staple of their diet. In California, most finch birds live in the coniferous forests and mountain ranges in the northern region of the Golden State. Finch birds are also perching birds, meaning most of them nest in tree branches. However, some of California's finches nest on mountain cliffs.

The Carduelis genus is one of the largest groups of wild finches. This group includes redpolls and siskin finches. California is home to five wild finch birds belonging to the Carduelis genus: American goldfinch, lesser goldfinch, Lawrence's goldfinch, common redpoll and pine siskin. The largest Carduelis finch bird in California is the pine siskin, which reaches lengths of 5.5 inches as adults. All of these birds feature solid-colored patches of feathers on their heads; the goldfinches have black-feathered heads, common redpolls have heads with red feathers and pine siskins have brown feathers on their heads.

The Carpodacus genus of finches are more commonly called rosefinches. This group of finches features red plumage on the breast and facial region. Most rosefinches occur in Asia, but three Carpodacus finches are native to North America. All three North American rosefinches include California in their range: Cassin's finch, purple finch and house finch. These finches are sexually dimorphic; the males feature the red plumage on their breast and face, while female have brown feathers all over their body. Males for all three rosefinch species have dark purple feathers on the remainder of the body.

Also referred to as mountain finches, the Leucosticte genus of birds have two species native to California, the black rosy-finch and gray-crowned rosy-finch. These birds get the rosy-finch part of their name from the bright pink plumage on their wings and tails. Black rosy-finch and gray-crowned rosy-finch live in the mountainous regions of North California such as the Sierra Nevada and Klamath Mountains. Both California mountain finches have short black legs and fork-shaped tails. For nesting, the black and gray-crowned rosy-finches develop bowl-shaped nests within the crevices of mountain cliffs.

Finches belonging to the Loxia genus of birds are also known as crossbills. They receive this name from their bill. Their bills' tips do not touch, but cross each other. Two birds in the Loxia genus live in California: the common crossbill and two-barred crossbill. The common crossbill is also known as the red crossbill, due to its reddish-orange plumage, while the two-barred crossbill is also the white-winged crossbill since it has white feathers on its wings. Like all members of the Loxia genus, both Californian crossbills' diets mainly consist of seeds from the cones of coniferous trees such as spruce, pine and redwood.