Cassin's Finch

Cassin's Finch (Haemorhous cassinii) is a stocky, medium-sized finch native to the coniferous forests of western North America. Named after the 19th-century Philadelphia ornithologist John Cassin, this bird belongs to the same genus as the House Finch and Purple Finch. While it strongly resembles these close cousins, Cassin's Finch is a specialist of mid- to high-elevation mountain zones. It is highly nomadic, particularly in winter, shifting its range dynamically based on the yearly productivity of conifer seed crops.

Separating Cassin's Finch from other Haemorhous finches requires close attention to head shape, back patterns, and undertail coverts.

Male Identification

• Head Shape: Features a distinctly peaked crown, looking noticeably more angular or pointed than the rounded head of a Purple Finch.
• Coloration: Males display a bright, raspberry-red cap that contrasts sharply with the brown, streaked nape and back. The throat and chest are a paler pinkish-rose, fading to a clean white belly.
• Back & Wings: The back is heavily and crisply streaked with dark brown lines, lacking the uniform reddish wash seen on Purple Finches.
• Undertail Coverts: Clean white base with fine, sharp, dark shaft streaks.

Female and Juvenile Identification

• Plumage: Plain grayish-brown overall with crisp, dark, narrow streaks over a clean white background on the underparts.
• Head Pattern: Lacks the dark, broad jaw stripe and bold white eyebrow of the female Purple Finch; instead, they have a subtle pale eye-ring and fine, dense streaks on the face.
• Bill: The bill is relatively long, straight-edged, and pointed compared to the slightly curved, bulbous bill of the House Finch.

Cassin's Finches are primarily birds of high, dry coniferous forests. During the breeding season, they occupy elevations ranging from 3,000 to over 10,000 feet, particularly favoring forests dominated by lodgepole pine, ponderosa pine, Douglas-fir, and subalpine fir.

Their geographic breeding range extends from southern British Columbia and Alberta down through the Rocky Mountains, Cascades, and Sierra Nevada to northern Baja California. In winter, they are altitudinal migrants, moving to lower valleys, pinyon-juniper woodlands, and suburban areas, occasionally irrupting far to the south and east into the desert Southwest and central Mexico.

Feeding and Diet

Cassin's Finches are primarily granivores. They feed extensively on the seeds of conifers, extracting them directly from cones or foraging on the ground for fallen seeds. They are also famous for eating the large, fleshy green buds of quaking aspens in early spring. During summer, they supplement their diet with wild berries and small insects, such as caterpillars and beetles.

Vocalization

The species is highly vocal. The flight call is a dry, rhythmic, three-syllable phrase often transcribed as chiddy-up or tid-a-lip, which reliably distinguishes it from other finches. The song is a rapid, long, musical warble. Uniquely among western finches, Cassin's Finches frequently incorporate high-quality mimicry into their songs, imitating the calls of nuthatches, bluebirds, and other forest neighbors.

Nesting

Nests are built high up in conifers, typically on a horizontal branch far out from the trunk. The female builds a cup of twigs, rootlets, and coarse grass, lining it with finer materials like hair and moss. She incubates a clutch of 3 to 5 bluish-green, dark-speckled eggs for about 12 to 14 days, while the male brings her food. Both parents actively feed the nestlings.