A challenging identification problem, at least for me, involves separating the Cassin’s finch (Haemorhous cassinii) from the purple finch (Haemorhous purpureus). These two finches to not overlap in the East. However, in the West there is limited overlap in the ranges of these two species, particularly in the breeding season. We live where the ranges of purple and Cassin’s finches overlap. I let these photographs, taken on different days in July, sit on my desk for weeks before finally deciding the birds were Cassin’s finches. Thank goodness for photographs for I never would be able to identify this bird on the wing. I welcome correction from a more experienced birder.
The male Cassin’s finch has a red crown that contrasts with its brown streaked nape. The red color on a Cassin’s finch is most pronounced on the crown, while the head has a peaked shape. The back is heavily streaked. Cassin’s finches are dimorphic, meaning the plumage of males differs from the plumage of females.Where the male Cassin’s finch has a rosy color, females are brown and streaked on the upper parts and white on the underside with crisp brown streaking. Both sexes have notched tails and thick, straight bills. They both have streaking on the undertail and often a thin eye-ring.
Many Cassin’s finches are resident although some are medium migrants moving to lower latitudes and lower elevations in the winter. Their habitat in the West is mountainous evergreen forests up to elevations of 10,000 feet. After the breeding season Cassin’s finches often join foraging groups of crossbills, pine siskins and other finches.
The Cassin’s finch’s diet consists mainly of seeds and tree buds, supplemented by fruits.
The red feather color is not produced by the Cassin’s finch. Rather the brilliant head feathers get their color from carotenoid pigments in the plants the bird eats.
The species name, cassinii, honors John Cassin (1813 – 1869) an ornithologist who first illustrated the finch that bears his name during the Pacific Railroad Survey of the 1850s.
Previously Cassin’s finches belonged to the Carpodacus genus. Recently the “purple” (Cassin’s, purple and house) finches were reclassified together as Haemorhous.
Cassin’s finches crave salt and are often found at mineral deposits on the ground. Almost every time Leonard and I stop where Modoc County Road 91 joins California Highway 139, where these pictures were taken, a small flock of finches is feeding on the road. Since there are not any obvious seeds on the road, we wonder if the Cassin’s finches perhaps obtain grit or minerals from the asphalt road surface.