This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the ferruginous hawk.
This is the largest of North American hawks, noticeably bigger than the familiar red-tailed hawk which we see here all year. Although we are not far outside the year-round range of the ferruginous, in our area this is strictly a late fall, early winter bird. It is most commonly seen here in December and January and then only in small numbers.
The ferruginous hawks that winter here are often seen looking for a meal near prairie dog towns. They are usually found in habitats with prominent perches: a lone tree, fence post, powerline pole or rocky outcrop. Small mammals — including prairie dogs, rabbits and gophers — comprise most of their diet, although they will also take birds, reptiles, amphibians and large insects.
In addition to searching for prey while perched or on the wing, these hawks may quietly wait outside a prairie dog hole to snatch the unlucky rodent when it emerges. On the ground these hawks may walk, hop or run after prey. The number of young raised each year is dependent on the cyclical abundance of its mammalian prey, and when food is scarce, pairs may not nest at all.
Ferruginous hawks are named for the rust-colored feathers on their backs and legs. They are one of the few “booted” hawks whose legs are covered in feathers all the way to the toes. In light-colored form, its white belly stands out, lacking the dark band of the common red-tailed hawk. A rare dark morph, sighted this winter in the Navajo lake area, appears dark brown all over when perched with white tail and flight feathers only apparent in flight. Both forms have a large bill with a long, yellow gape that extends back as far as the eyes.
Ferruginous hawks are birds of the open spaces of the West, dependent on the conservation of the grassland, prairie, sagebrush and edge habitats where they hunt.
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Photo courtesy Jeffrey Reichel