Ferruginous Hawk (Buteo regalis)

Description
Ferruginous Hawk

Size

  • Ferruginous hawks are the largest of the hawks soaring in North America.
  • Adults are large, heavy, thick-set birds measuring 63 centimetres (25 inches) long.
  • Adult female ferruginous hawks may be up to one-third larger than adult males.

Appearance

  • The name ferruginous comes from the Latin word ferrugo, meaning rust. As its name suggests, the ferruginous hawk is a light colored hawk with a rust-colored back.
  • The head is somewhat lighter in color than the rusty back and the tail is light and unbanded.
  • From below, a typical adult shows a dark V formed by rusty feathers on the legs. The breast, abdomen and under-wings are primarily white.
  • Dark phase ferruginous hawks are dark brown with some feathers edged in rusty brown.
Distribution

  • In winter, ferruginous hawks migrate from the southern portion of the prairie provinces to the southwest United States and Mexico.
  • Ferruginous hawks banded in Alberta have been found wintering in Colorado, New Mexico, Kansas, Texas, and California.
Natural History

Habitat

  • Ferruginous hawks are birds of the arid grassland regions of the province, and are found in areas of uncultivated pastureland or prairie.
  • Along with burrowing owls, ferruginous hawks are the only raptors (birds of prey) that use the grasslands as their main habitat.
  • The large body and broad wings of ferruginous hawks are well adapted to soaring on thermal updrafts over the prairies or giving a rapid straight-a-way chase of prey animals.
  • They are completely unsuited to dipping and turning among trees or shrubs in habitats with heavy cover.

Food

  • In Alberta, the ferruginous hawk feeds mainly on rodents. Ground squirrels make up nearly 90% of the diet.
  • While raising their young, one pair of ferruginous hawks consumes an average of 480 ground squirrels.
  • Other prey includes:
    • Mice
    • Voles
    • White-tailed Jackrabbits

When Active

  • Like most Alberta raptors, ferruginous hawks are found in the province only during the summer months. In general, they:
    • Arrive in late March, returning in the spring just as ground squirrels are becoming active after their winter hibernation.
    • Nest and raise their young from mid-April to late July
    • Migrate southwards in September and October
  • Ferruginous hawks hunt during the day when ground squirrels are active.
Reproduction and Growth

Breeding Behaviour

  • Each year individual birds return to the same nesting area and, often, the same nest.
  • In Alberta, nests are usually built:
    • In low trees
    • On the ground
    • On cliffs found in the badlands area of the grassland region
  • Nests are built largely of sticks and roots and are often lined with dead grass, sod, or occasionally paper.
  • Cow dung is found in and characteristic of most ferruginous hawk nests. As the dried dung breaks down, it provides a soft lining for the nest.
  • New sticks and twigs are added each year to the nest until it becomes quite bulky.
  • A breeding pair may have up to five nests in their territory but use only one each year.
  • Three to five eggs are laid and incubated for about a month.
  • The eggs hatch about the same time as young ground squirrels become active above the ground.

Growth Process

  • Ferruginous hawks usually mature at three years of age and may live up to 15 or 20 years in the wild.
Conservation and Management

Status

The ferruginous hawk is classified as At Risk in the General Status of Alberta Wild Species report. See:

Also see the Status of the Ferruginous Hawk in Alberta report at:

This bird species is also listed as endangered under the Wildlife Act. See th. See the Species at Risk profile for this species at:

Issues

  • In recent years, the number of ferruginous hawks has been declining in Alberta, as a result of loss of nesting habitat.
  • Fewer than 700 pairs are estimated in the province.

Current management

As a Threatened species, the ferruginous hawk is protected by the provincial Wildlife Act and it is illegal to kill or harass individuals or disturb their nests at any time of the year. This species is the subject of recovery planning and implementation in Alberta. The recovery plan for this species can be found at:

The ferruginous hawk is a focal species of the MULTISAR (multiple species at risk) program. See:

Similar Species

The ferruginous hawk, like the rough-legged hawk, has feathers on the legs but the ferruginous hawk possesses a longer tail and wings.

 

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UUpdated: Jan 8, 2014