Finches: Fringillidae

Physical characteristics: Red crossbills show much geographic variation in body size, and in bill size and shape, but not in color. They have a fairly heavy body (about the size of sparrows), a short forked tail, and a stout bill where the tips of the upper and lower mandibles (parts of bill) cross over. Males are colored an overall dusky brick red with dusky wings that have reddish edging, and a dusky black tail that is short and notched. The undertail coverts are dark with whitish edging, while the belly is whitish gray. Females are gray tinged with dull green, brightest on rump, with darker (dusky black) wings. Juveniles have weakly crossed mandibles, gray-olive upperparts, whitish under parts that are streaked with dark brown and washed with yellow, and a buff-yellow rump. Adults are 5.3 to 6.5 inches (14.0 to 16.5 centimeters) long and weigh about 1.4 ounces (40 grams). Their wingspan is 10.0 to 10.8 inches (25.4 to 27.4 centimeters) long.

Geographic range: Red crossbills range through the boreal and montane forest regions of both North America and Eurasia. They are found from coast to coast on both continents, breeding from southern Alaska, Manitoba, Quebec, and Newfoundland, south in west to northern Nicaragua, in eastern United States to Wisconsin and North Carolina.

Habitat: Red crossbills are mostly found in pine-containing conifer forests.

Diet: Their diet consists of conifer seeds mostly from the tree but sometimes off the ground, especially liking pine seeds. They remove seeds with its crossed bills and flexible tongue. The birds also eat insects and caterpillars.

Behavior and reproduction: Red crossbills are very social birds, especially during their nonbreeding season when they are found in large flocks. They sing a series of two-note phrases followed by a trilled warble, such as "jitt, jitt, jitt, jiiaa-jiia-jiiaaaa," "chipa-chipa-chipa," and "kip-kip-kip." The birds defend their territory with a repeated series of simple chirps as they fly around. During courtship, males fly above a female while vibrating wings and singing. Breeding pairs are monogamous. Females build saucer-shaped nests of twigs, grass, bark strips, and rootlets. Nests are lined with finer grasses, fur, feathers, hair, and moss, located near the end of conifer branches, and 6.6 to 40.0 feet (2 to 12 meters) off the ground. Females lay three to four light green-blue eggs that are spotted with brown and lilac. The incubation period is twelve to eighteen days. Only females incubate. The helpless newborns are brooded by the female and fed by both parents. The fledgling period is fifteen to twenty days. One to two broods occur each year.

Red crossbills and people: There is no known significant relationship between people and red crossbills.

Conservation status: Red crossbills are not threatened. They are abundant throughout their range, but some species are declining in numbers due to human activities such as logging operations. ∎