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Gray Hawk
Buteo nitidus

Status: Lower risk

Population Trend: Stable.

Other Names: Asturina nitida, Buteo nitida, Gray Goshawk, Gray-lined Hawk, Grey Hawk, Grey-lined Hawk, Mexican Goshawk (plagiatus), Nicaraguan Goshawk, Shining Buzzard Hawk (pallidus).


Buteo nitidus
click to enlarge
Distribution: Nearctic/Neotropical. Southwestern United States south along both slopes of Middle America and South America west of the Andes to western ECUADOR and east of the Andes to northern ARGENTINA, PARAGUAY, and southern BRAZIL. more....

Subspecies: 3 races. B. n. plagiatus: Southwestern UNITED STATES (Texas, New Mexico, and Arizona) south to northwestern COSTA RICA (Guanacaste); Bay Islands of HONDURAS; B. n. nitidus: Southwestern COSTA RICA to northern COLOMBIA and western ECUADOR, eastern COLOMBIA, and eastern ECUADOR, east to VENEZUELA and the GUIANAS and south through Amazonian BRAZIL to northern Maranhno; TRINIDAD; B. n. pallidus: South-central BRAZIL and eastern BOLIVIA south to PARAGUAY and north-central ARGENTINA. more....

Taxonomy: The generic placement of this species has been perenially uncertain. Throughout the latter part of the twentieth century, most authors included it in Buteo because it was thought to be most closely related to the "woodland buteos," including B. magnirostris, B. ridgwayi, B. platypterus, and B. lineatus (Johnson and Peeters 1963). The Gray Hawk was returned to a separate genus, Asturina, by Amadon (1982), who pointed out that it shared more characters with the sub-buteonine genera Leucopternis and Buteogallus than with Buteo, a view shared by Millsap (1986). This treatment was followed by Sibley and Monroe (1990) and AOU (1998), but not by Thiollay (1994). The recent molecular studies of Reising et al. (2003) showed that the Gray Hawk should be placed within Buteo, but that the "woodland buteos" do not represent a monophyletic group. This recommendation was recently adopted by the AOU Committee on Classification and Nomenclature (Banks et al. 2006), and the AOU's South American Classification Committee (Remsen et al. 2008). Based on analyses of mitochondrial and nuclear genes, Lerner et al. (2008) confirmed that B. nitidus is more closely related to two Leucopternis species than to B. lineatus and B. platypterus, so further study is still necessary to clarify these relationships. more....

Movements: Partial migrant (Bildstein 2006). Northern breeding populations in Arizona, western Texas, and northern Sonora migrate southward in the non-breeding season (Howell and Webb 1995, AOU 1998).

Habitat and Habits: Occurs in lowlands in broken forest, forest edges, and savannas and pastures with trees more than in continuous forest. May perch on power poles, or on an exposed tree in more open country, but more retiring than the Roadside Hawk and a bit less common in most areas in similar habitat. It also may hunt more on the wing (Lowery and Dalquest 1951). Russell (1964) thought that this species is more often found in the border between tall forest and clearings than the Roadside Hawk in Belize, but in French Guiana, Thiollay (2007) found the Gray Hawk using more forested habitats than the Roadside Hawk. Soars fairly frequently at low heights. Observers often comment on its tameness.more....

Food and Feeding Behavior: Feeds on snakes, lizards, frogs, small mammals, birds, and insects. Voous (1969) suggested that this species is more of a bird hunter than the Roadside Hawk. Perches mainly in the canopy and waits to ambush prey by dropping on it in a downward glide, or pursuing it in active flight (Haverschmidt 1962). more....

Breeding: The nest is a platform of sticks lined with fresh green leaves and placed in the crotch of an evergreen tree, or, less often, in a dead tree. Clutch size is 1-4 (usually 2) eggs, which are white or bluish-white, rarely with a few reddish-brown markings. The nestling period is about 42 days (Gibbs and Gibbs 1975). Re-nesting may occur after a nest fails, as suggested by Patrikeev (2007) in Texas. more....

Conservation: Fairly common to common in most parts of its extensive range and may be expanding its range in some regions (e.g., Nicaragua) where forests are being replaced by second-growth. No longer listed as a U.S. Federal Species of Concern (U.S. Fish and Wildlife Service 2003) and categorized as a species of "Least Concern" by BirdLife International.more....

Important References: 
Bent, A.C. 1937. Life histories of North American birds of prey. Order
  Falconiformes (Part 1). U.S. National Museum Bulletin no. 167.
Bibles, B.D., R.L. Glinski, and R.R. Johnson. 2002. Gray Hawk Asturina
  nitida
. In A. Poole and F. Gill (eds.), The Birds of North America no.
  652. Academy of Natural Sciences, Philadelphia, PA.
Bierregaard, R.O. 1994. Grey Hawk. P. 176 in del Hoyo, J., A. Elliott, and
  J. Sargatal (eds). Handbook of birds of the world. Vol. 2. New World
  vultures to guineafowl. Lynx Edicions, Barcelona, Spain.
Glinski, R.L. 1988. Gray Hawk. Pp. 83-86 in R.L. Glinski, B. Giron
  Pendleton, M.B. Moss, M.N. LeFranc,Jr., B.A. Millsap, and S.W. Hoffman
  (eds.), Proceedings of the Southwest Raptor Management Symposium and
  Workshop. National Wildlife Federation Scientific and Technical Series no.
  11. National Wildlife Federation, Washington, D.C.
Millsap, B.A. 1986. Biosystematics of the Gray Hawk, Buteo nitidus
  (Latham). M.S. thesis, George Mason University, Fairfax, VA.
Navarro R., R., E. Gedio Marín, and J. Muñoz G. 2007. [Notes on the
  reproductive ecology of three accipiters in Venezuela]. Ornitologia
  Neotropical 18:453-457. (In Spanish with English summary)
Palmer, R.S. 1988. Gray Hawk. Pp. 402-410 in R.S. Palmer (ed.), Handbook
  of North American birds. Vol. 4. Diurnal raptors. Yale University Press, New
  Haven, CT.
Stensrude, C. 1965. Observations on a pair of Gray Hawks in southern
  Arizona. Condor 67:319-321.
Williams, S.O., III, and D.J. Krueper. 2008. The changing status of the
  Gray Hawk in New Mexico and adjacent areas. Western Birds 39:202-208.
more....

Sites of Interest:
VIREO
Gray Hawk photos.
Xeno-canto
Vocalizations.
Aves de Rapina de Brasil
Species account with emphasis on Brazil.

Researchers:
Millsap, Brian
Perez, Julio
Ramos, Ernesto
Zorzin, Giancarlo

Last modified: 9/19/2011

Recommended Citation: Global Raptor Information Network. 2014. Species account: Gray Hawk Buteo nitidus. Downloaded from http://www.globalraptors.org on 23 Apr. 2014








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