This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the blue grosbeak.
Birds known as grosbeaks all possess big, chunky bills which they use to crack open hard-shelled seeds, but they are not necessarily closely related to each other. Evening and pine grosbeaks are members of the finch family. The other grosbeaks in the United States, the rose-breasted, the black-headed and the blue, are all members of the cardinal family, which includes colorful red, yellow and blue birds.
Deep blue body color and chestnut-colored wingbars are marks of the male blue grosbeak in breeding plumage. Females and immature males are cinnamon-colored with brown wingbars. A large, triangular bill dominates the face.
These striking birds nest across the southern United States and they have been extending their range northward. They winter or are resident birds in Mexico and in parts of the Caribbean. Within the areas where they are found, they are widespread, but not found in abundant numbers.
Blue grosbeaks are denizens of tangled vine and shrub habitats. They thrive in abandoned agricultural land but tend to avoid suburban habitats. In the southwestern U.S., they most commonly nest near water in streamside thickets. On occasion they show up to gather seed from the ground under backyard feeders.
In summer, a male often gives away his otherwise hidden location when he sings his rambling song from high exposed perches. Pairs may defend a breeding territory ranging from two to 20 acres where the female builds a nest low in a small tree or shrub. In southern parts of their breeding range, the female commonly leaves care of the fledglings to the male while she builds a second nest and hatches a second brood.
Their heavy bills allow them to eat large insects, including grasshoppers and crickets. They hover and glean insects from foliage, sally out to catch flying prey and hunt on the ground. Before feeding an insect to their nestlings, they carefully remove the head, wings and legs. Later in the season they also eat seeds and waste grains.
Along with the black-headed grosbeaks, blue grosbeaks will be departing soon, not to return until next spring.
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