Buteo ventralis

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Rufous-tailed Hawk
Buteo ventralis


Status: Near Threatened

Population Trend: Unknown.

Other Names: Buteo pictus, Patagonian Red-tailed Buzzard, Red-tailed Buzzard, Rufous-tailed Buzzard.

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Distribution: Neotropical. Southern CHILE (Ñuble) and south-central ARGENTINA (Rio Negro) south through Patagonia and the Straits of Magellan; possibly breeds on TIERRA DEL FUEGO (Isla Grande). more....

Subspecies: Monotypic.

Taxonomy: Amadon (1964, Amadon and Bull (1988), and Clark (1986) suggested that this form should be treated as a race of the Red-tailed Hawk. The molecular studies of Riesing et al. (2003) also revealed little divergence between B. ventralis and B. jamaicensis, and they suggested that further study may show that it is only an austral race of the latter species. Bildstein (2004) hypothesized that this form may have derived from the Red-tailed Hawk as a result of "migration dosing," which occurs in areas of misdirected migration, stranding isolated individuals unable to return to their usual breeding grounds.more....

Movements: Irruptive or local migrant, with juveniles dispersing from breeding areas (Bildstein 2006). Other authorities have categorized it as sedentary, locally dispersive, or as an altitudinal migrant (Bierregaard 1994, Rozzi et al. 1996, Ferguson-Lees and Christie 2001, Bildstein 2004 ), although Pastore et al. (2007) noted that there are no direct observations of the latter behavior. Trejo et al. (2006) suggested that observations of Gunnar Höy in Chebez (1994) and Olrog (1949) could indicate migrants or wandering birds, and migrating flocks of hawks were observed flying northward in April across Volcan Lonquimay in southern Chile by Lorenzo Sympson in 2004 (pers. comm. to Trejo et al. op cit.). Birds breeding on Tierra del Fuego are thought to migrate north to the South American mainland in the austral winter (Humphrey et al. 1970).more....

Habitat and Habits: Some authors (e.g., Blake 1977) have described the habitat preferences of this species as mature forest and new growth in burned-over areas, but Humphrey et al. (1970) and Venegas and Jory (1979) regarded it as an open country species, and Estades (2004) found it in pine plantations. In Argentina, Gelain and Trejo (2001) observed it in pure beech forest, but Imberti (2003) found it in the transition zone between Nothofagus forest and steppe. Figueroa et al. (2000), Trejo et al. (2006), and Rivas e al. (2009) suggested that its ideal habitat is a mixture of forest patches with large trees for nesting and peching adjacent to open areas for foraging. Rivas et al. (2009) found active nests in Chile in primary laurifolia forest, either continuous or fragments (>80 ha). Apparently, this species is never recorded in heavily human-modified areas (Jaksic et al. 2001). more....

Food and Feeding Behavior: Like the closely related Red-tailed Hawk, this species is apparently a dietary generalist (Figueroa et al. 2000). Based on a review of the sparse literature on this topic, Trejo et al. (2006) stated that at least three species of mammals, eight of birds, one snake, and two orders of insects have been documented as prey items (Housse 1945, Behn 1947, Greer and Bullock 1966, Markham 1970, Figueroa et al. 2000), with frequently mentioned species including European Hare, Chilean Pigeon, Southern Lapwing, Austral Thrush, Chilean Tinamou, and unidentified rodents. A detailed study in Chile by Figueroa et al. (2000) showed a broad diet consisting of small mammals (38%), birds (55.3%), reptiles (3.5%), and insects (3.5%). Generally hunts from a perch, either a fencepost (Bernath 1965) or a large tree with dense foliage (Behn 1947, R. Figueroa unpubl.). more....

Breeding: According to Trejo et al. (2006), only five nests have been reported (all from Chile), and they were all large platforms made of interwoven dry sticks placed on live trees more than 25 m tall and more than 100 cm in diameter (Housse 1945, Behn 1947, Figueroa et al. 2001). The nests were placed on forked branches closed to the main trunk or on a thick horizontal branch in the upper part of the trees. There are no published details on clutch size, except that Housse (1945) collected three juveniles from a nest, and Behn (1947) found only a single young (also collected) in another nest; R. Figuero (unpubl.) also saw only a single young in another nest in Cerro Ñielol, Chile. The eggs are undescribed in the literature. Rivas et al. (2009) are conducting studies of the breeding habits of this species in Chile which should fill in the major gaps in our knowledge. more....

Conservation: Scarce throughout its range and possibly Vulnerable, but too little is currently known about its population size and trends to accurately categorize this species. Trejo et al. (2006) suggested that it is at risk because is dependent on a specific type of forested habitat, which is being lost from afforestation and conversion to agriculture. Listed as Rare, Vulnerable, or inadequately known in Chile and Argentina (Glade 1988, Rottman and López-Calleja 1992, Ortiz et al. 1994, Chébez 1994, Fraga 1997, Jaksic et al. 2002). BirdLife International provisionally categorizes it as "Near Threatened." more....

Important References:
Behn, F. 1947. [Contribution to the study of Buteo ventralis.] Boletin de
  la Sociedad de Biologia de Concepcion 22:3-5. (In Spanish)
Bierregaard, R.O. 1994. Rufous-tailed Hawk. Pp. 189-190 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.
Clark, W.S. 1986. What is Buteo ventralis? Birds of Prey Bulletin
  3:115-118.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Figueroa, R., J.E. Jiménez, C.E. Bravo, E.S. Corales. 2000. The diet of
  the Rufous-tailed Hawk (Buteo ventralis) during the breeding season in
  southern Chile. Ornitologia Neotropical 11:349-352.
Goodall, J.D., A.W. Johnson, and R.A. Philippi. 1951. [The birds of Chile.
  Vol. II]. Establecimientos Gráficos Platt SA, Buenos Aires, Argentina. (In
  Spanish)
Imberti, S. 2003. Notes on the distribution and natural history of some
  birds in Santa Cruz and Tierra del Fuego Provinces, Patagonia, Argentina.
  Cotinga 19:15-24.
Jaksic, F.M., and J.E. Jiménez. 1986. The conservation status of raptors
  in Chile. Birds of Prey Bulletin 3:96-104.
Johnson, A.W. The birds of Chile and adjacent regions of Argentina,
  Bolivia and Peru. Vol. 1. Platt Establicimientos Gráficos, Buenos Aires,
  Argentina.
Norambuena, H.V., V. Raimilla, and J.E. Jiménez. 2012. Breeding behavior
  of a pair of Rufous-tailed Hawk (Buteo ventralis) in southern Chile. Journal
  of Raptor Research 46:211-215.
Pastore, H., S.A. Lambertucci, and M. Gelain. 2007. Rufous-tailed Hawk
  (Buteo ventralis) in Argentina Patagonia. Pp. 106-118 in K.L. Bildstein,
  D.R. Barber, and A. Zimmerman (eds.), Neotropical raptors. Hawk Mountain
  Sanctuary, Orwigsburg, PA.
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.
more....

Current Research: The recent reviews by Trejo et al. (2006) and Pastore et al. (2007) are the most comprehensive sources of information on this species, and each has contributed extensively to this species account.

Researchers:
Alvarado Orellana, Sergio Alfredo
Barbar, Facundo
Lambertucci, Sergio
Marin, Manuel
Norambuena, Heraldo V.
Raimilla Almonacid, Victor
Silva-Quintas, Carlos

Last modified: 6/25/2012

Recommended Citation: Global Raptor Information Network. 2013. Species account: Rufous-tailed Hawk Buteo ventralis. Downloaded from http://www.globalraptors.org on 21 May. 2013