Buteo albigula

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White-throated Hawk
Buteo albigula


Status: Lower risk

Population Trend: Unknown.

Other Names: Lesser Buzzard.

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Distribution: Neotropical. Breeds in southern CHILE (Aysén) and southern ARGENTINA; non-breeding migrants occur from northwestern VENEZUELA (Mérida) and COLOMBIA south along the eastern Andes through ECUADOR, PERU, BOLIVIA, and northwestern ARGENTINA. more....

Subspecies: Monotypic.

Taxonomy: Considered to be a race of B. platypterus by Phillippi (1943), but it was later included under B. brachyurus (Hellmayr and Conover 1949, Rand 1960, Amadon 1964, Amadon and Bull 1988). The two forms may be sympatric in Colombia (Lehmann and Haffer 1960), and no interbreeding has been reported. Most recent authors, including Sibley and Monroe (1990) and Thiollay (1994) consider them to form a superspecies.

Movements: Partial migrant, according to Bildstein (2006), although at least some populations are apparently completely migratory. Observations of this species in the Yungas region of the provinces of Tucumán and Salta (Höy 1969, Olrog 1985), where the species is not known to breed, was the first indication that it might be migratory, and Johnson (1965) had earlier mentioned sightings in northern Chile. Pavez (2000) reported migratory movements of hundreds of individuals in central Chile, and he suggested that the individuals encountered in northern South America are all migrants from austral regions. This notion was also supported by Ridgely and Greenfield (2001) for Ecuador, based on the known dates of occurrence, although Niels Krabbe has seen birds there year-round (Trejo et al. 2006). Central Argentine populations may migrate to northern Argentina (Salta and Tucumán), and Gelain et al. (2001) found it only in the breeding season in northwestern Argentine Patagonia during a 10-year study in the Nahuel Huapi Lake region. This species is also an altitudinal migrant in some areas. more....

Habitat and Habits: Occurs at middle and montane elevations, but occasionally ranges lower in the southern portion of breeding range in Chile and Argentina. In its breeding range, this is an indicator species of temperate southern beech (Nothofagus) forests from 900-1,600 m elevation (Pavez et al. 2004, Trejo et al. 2004). In its winter range in Colombia, it is found in humid montane forest, especially low or elfin forest above 2,500 m (Hilty and Brown 1986), including disturbed areas. However, it occurs in dry, non-native eucalyptus forests in Ecuador (Henry and Aznar (2009) and in Araucaria woodlands farther south (Fjeldså and Krabbe 1990). The hunting territory extends to the forest edges and to the grasslands above tree-line (Figueroa et al. 2001, Trejo et al. 2006). Soars often, but not as much as the similar Short-tailed Hawk. Breeding birds can be tolerant of human presence (Gelain et al. 2001). more....

Food and Feeding Behavior: Feeds on birds, rodents, snakes, and lizards during the breeding season, and adults also provided these prey items to nestlings (Figueroa et al. 2001, Trejo et al. 2001, Pavez et al. 2004, Trejo et al. 2004). Pavez (2000) observed up to 70% of migrating and stationary hawks feeding primarily on insects during migration in central Chile (Pavez 2000), catching them in flight. This species was formerly thought to hunt mostly from a concealed perch from where it ambushed prey, but Figueroa et al. (2001) recorded hovering, quartering flights, and low-level flights in pursuit of avian prey, especially along ridgetops. Of these hunting methods, hovering seemed to be the most frequent. According to Trejo et al. (2006), P. Capllonch saw these hawks pursuing tinamous in northeastern Argentina. more....

Breeding: Builds a stick nest placed on a cliff or in a tree, usually a Nothofagus, in Argentina (Trejo et al. 2004) and Chile (Pavez et al. 2000), but one nest was in a "peumo" (Cryptocarpa alba) tree in Chile (Pavez et al. 2004). Nests are often re-used, growing larger with each successive season (Trejo et al. 2004). Clutch size is 1-2 eggs, although de la Peña (1992) reported a clutch size of 2 or 3 eggs. The pairs studied by Trejo et al. (op cit.) and Pavez et al. (op cit.) raised only a single young in each nesting attempt. The egg is white and unmarked, and a single specimen from Argentina measured 50.23 x 39.98 mm (Trejo et al. op cit.). Most, but not all, incubation is done by the female, and most prey is delivered to the nest by the male. The incubation period lasts for about one month, and the nestling period is about six weeks (Trejo et al. op cit.). more....

Conservation: Still not well known and generally regarded as rare or uncommon throughout its breeding range, but several recent studies and an increasing number of records suggest that it may be more common than previously realized (Casas and Gelain 1995, Gelain et al. 2001, Trejo et al. 2001, 2006). It is categorized as a species of "Least Concern" by BirdLife International (2008). Pavez (2000) and Figueroa Rojas et al. (2001) felt that the main threat to these small woodland hawks was the rapid removal of their temperate forest habitat in southern Chile, and Trejo et al. (2004) made similar statements regarding its status in Patagonian Argentina. more....

Important References:
Bierregaard, R.O. 1994. White-throated Hawk. Pp. 180-181 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.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Pavez, E.G. 2000. Migratory movements of the White-throated Hawk Buteo
  albigula in Chile. Journal of Raptor Research 34:143-147.
Pavez, E.F., C. González, B.A. González, C. Saucedo, S. Alvarado, J.P.
  Gabella, and A. Arnello. 2004. Nesting of the White-throated Hawk (Buteo
  albigula) in deciduous forests of central Chile. Journal of Raptor
  Research 38:186-189.
Trejo,A., R.A. Figueroa, S. Alvarado O. 2006. Forest-specialist raptors of
  the temperate forests of southern South America: a review. Revista
  Brasileira de Ornitologia 14:317-330.
Trejo, A., V. Ojeda, M. Kun, and S. Seijas. 2006. Prey of White-throated
  Hawks (Buteo albigula) in the southern temperate forest of Argentina.
  Journal of Field Ornithology 77:13-17.
Trejo, A., V. Ojeda, L. Sympson, and M. Gelain. 2004. Breeding biology
  and nest characteristics of the White-throated Hawk Buteo albigula in
  northwestern Argentine Patagonia. Journal of Raptor Research 35:169-170.
more....

Current Research: The review by Trejo et al. (2006) is the most comprehensive source of information on this species, and it has contributed extensively to this species account.

Sites of Interest:

Xeno-canto
Vocalizations.

Researchers:
Alvarado Orellana, Sergio Alfredo
Barbar, Facundo
Bechard, Marc J.
Escobar Gimpel, Víctor Mauricio
Lambertucci, Sergio
Marin, Manuel
Norambuena, Heraldo V.
Raimilla Almonacid, Victor
Sympson, Lorenzo

Last modified: 4/11/2010

Recommended Citation: Global Raptor Information Network. 2013. Species account: White-throated Hawk Buteo albigula. Downloaded from http://www.globalraptors.org on 12 Dec. 2013