Ferruginous hawks are the biggest hawks in North America. Females may be as much as one-and-a half times larger than males. Adults are a rusty color on their shoulders and back and down to their legs. The belly is whitish, spotted with reddish brown. The leg feathers make a V shape against the hawk's belly, as seen when they are flying. When perching, the gray tips of the long, broad wings can reach the tip of their tail, which is white, gray and rust colored. Young Ferruginous hawks don’t have rust colored legs and there is less color on their backs.
The Ferruginous hawk occurs in western and central part of North America. Its range stretches from the southern Canada to the south USA and north Mexico. Its preferred habitat includes lowlands, plateaus, plains, valleys, agricultural land rolling hills of grass land, ranches, and the desert edges.
The Ferruginous hawk hunts during the day. It favors a solitary lifestyle, pairing up only during the breeding season. They generally build nests on cliffs and in isolated trees. Their nests make use of wide variety of structures, including utility structures, abandoned farm machinery, farm buildings, artificial platforms and haystacks. Each day they hunt and patrol their territory. Ferruginous hawks make a 'kaah-kaah' call when communicating with other hawks. They line their large stick nests with shredded bark, grass or dried cow dung. The hawk often rests on the ground but is wary of humans and is secretive.
Ferruginous hawks are carnivorous, eating ground squirrels, mice jackrabbits, birds, amphibians and reptiles. Sometimes they will eat meadowlarks, snakes, lizards, grasshoppers, and crickets.
Ferruginous hawks are monogamous, keeping the same mate for their entire life. Males and females are seen together only during the breeding season, between March and June. Having chosen a suitable place for their nest, males bring in the building material, while females do most of the construction. They copulate during the nest-building period and the female will lay up to 4 eggs with two days between laying. The parents work in shifts, spending equal amounts of time in incubating the eggs. After up to 35 days, the eggs hatch and the nestlings depend for the next 40-50 days on their parent until they are fully developed. They are able to breed at two years old.
Their major threat is human occupation, as this leads to loss of nesting sites. Their main breeding habitat is constantly disturbed by farmers, who will occasionally take their chickens. This disrupts breeding patterns and the size of clutches. When several pairs are nesting close to each other, this causes constant conflict.
No recent estimate of population size is available for Ferruginous hawk. IUCN lists them as Least Concern (LC), their population flourishing over a huge range of North America. Indeed, the population has increased over the last 40 years by 155%. In 1984, the population estimate for North America was between 3,000 and 4,000 pairs, and in 1987, it was 14,000 individuals.
Ferruginous hawks help to control the rodent population.