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Ferruginous Hawk - BirdForum Opus

Adult light morph
Photo © by Marysan
Ramona, California, 18 February 2005

Alternative name: Ferruginous Rough-legged Hawk

Buteo regalis

Identification

Dorsal view
Photo © by digishooter
Kelso Valley, Kern County, California, USA,
5 March 2012

Length 50–66 cm (19¾-30in; wingspan 134–152 cm (52¾-60in)
This is the largest North American Buteo occurring in two distinct color morphs. Dark morphs comprise fewer than 10% of birds breeding in Alberta and fewer than 5% elsewhere. It is a large, massive hawk with broad wings, a large head, wide gape, and robust chest legs and feet. Tail is white with variable rusty or gray tip. Adult light morph is mostly white with pale gray head and rusty mottling on wing coverts and thighs. Dark morph is all chocolate-brown or blackish with white tail and remiges tipped variably with dusky. The juvenile light morph is similar to the adult but lacks the rusty mottling on its leg feathers. Males and females are similar with females averaging slightly larger.

Similar Species

Juvenile showing mostly white leg feathers
Photo © by Joseph Morlan
Point Reyes, California, 16 October 2004

Dark morph may be confused with dark morph Rough-legged Hawk but has a different tail pattern, more extensive white in secondaries and much larger head and bill. Adult light morph Rough-legged Hawk may lack dark belly band and be confused with Ferruginous. Light morph birds sometimes confused with Red-tailed Hawk which usually has a dark head and more of a dark belly band. Red-tail has a characteristic dark leading edge to its wing (patagium) which Ferruginous Hawk lacks. Dark morph also may be confused with Golden Eagle which is even larger with much longer wings showing pinched in wings at the body.

Distribution

Light morph adult
Photo © by Joseph Morlan
Panoche Valley, Paicines, California, USA,
28 February 2021

Breeds from southwestern Canada south nearly to Mexico. Winters south into Mexico. Accidental vagrant to the midwestern United States.

Taxonomy

Adult dark morph
Photo © by Joseph Morlan
Salt Springs Valley, Calaveras County,
California, USA, 16 November 2018

This is a monotypic species[1].

Habitat

Open prairie, fields, farmland, rice fields, open country, marshes.

Behaviour

Diet

Includes prairie dogs and ground squirrels. Usually forages from the ground.

Breeding

Nests initiated from March to May depending on latitude; in Canada, laying about 2 weeks later than in center of range. Large, bulky stick nest usually on cliff face or situated on the remains of pre-existing hawk or crow nests. May use artificial nest platforms. Average annual clutch varies from 2 to 4 eggs, but can range from 1 to 8. Young typically first leave the nest at 38–50 days.

Vocalisations

Usually silent. Screams and calls accompany flight displays. Alarm Call, kree-a or kaah kaah, is described as similar to that of Herring Gull

References

  1. Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2018. The eBird/Clements checklist of birds of the world: v2018. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
  2. Ng, J., M. D. Giovanni, M. J. Bechard, J. K. Schmutz, and P. Pyle (2017). Ferruginous Hawk (Buteo regalis), version 2.0. In The Birds of North America (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.ferhaw.02
  3. Schmutz, J. K. and S. M. Schmutz. (1981). Inheritance of color phases of Ferruginous Hawks. Condor no. 83:187-189.
  4. White, C.M., Boesman, P. & Marks, J.S. (2018). Ferruginous Hawk (Buteo regalis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53143 on 20 November 2018).
  5. Ferruginous Hawk Tri-National Migration Study
  6. BirdForum Member observations

Recommended Citation

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