Summer residents of western North America, from the High Plains to the Pacific Coast and from southwestern Canada to northern Mexico, black-headed grosbeaks favor riparian woodlands where they feed on a wide variety of insects, seeds and berries. Despite their thick, conical bills and bulky stature, they are known for their melodious song, which is delivered by adult males and females.
Along the Colorado Front Range, black-headed grosbeaks are best found across the lower foothills, generally between elevations of 6000 and 8000 feet. They are easily attracted to backyard feeders in that life zone and may wander onto the Piedmont for handouts as well. In all parts of their range, nests are placed in dense vegetation near streams and both parents participate in incubation and childcare duties. Both parents also vigorously defend their nest site from potential predators such as jays, crows and magpies.
By late summer, black-headed grosbeaks head for Mexico, sometimes traveling in sizable flocks. There they spend the winter, adding monarch butterflies to their omnivorous diet (one of the few species unaffected by the protective toxins within those colorful insects).
