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Ridgway's Hawk
Buteo ridgwayi

Status: Critically endangered

Population Trend: Unknown.

Other Names: Hispaniolan Hawk, Ridgway's Haitian Insect Hawk.

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Buteo ridgwayi
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Distribution: Neotropical.  Endemic to Hispaniola (Dominican Republic, Haiti, and adjacent islets), but now surviving only in the Dominican Republic. The status of the islet populations requires confirmation, but they are probably extinct. more....

Subspecies: Monotypic.

Taxonomy: Johnson and Peeters (1963) hypothesized that B. ridgwayi is closely related to a group of mainland Buteo species, including B. nitidus (= Asturina nitida), B. platypterus, and B. magnirostris, and they suggested that the species in this group are closer to Leucopternis than to other Buteo species. However, Amaral et al. (2009) found that the closest continental relative of B. ridgwayi is the Red-shouldered Hawk (B. lineatus), based on molecular evidence, and it may have originated through the process of "migration dosing," where displaced migrants establish breeding populations on islands (Bildstein 2004).

Movements: Non-migratory.

Habitat and Habits: Although this species appears to prefer undisturbed forest in lowlands and foothills, it has actually been reported from a wide variety of habitats, including rainforest, subtropical dry and moist forests, pine forest, limestone karst forest, and even in second-growth woodlands and agricultural areas from sea level to 2,000 m (Wiley 1986, Keith et al. 2003, Thorstom et al. 2007). The observations of Thorstrom et al. (2007) of 74 pairs in the Los Haitises National Park showed that a majority of the birds occurred in degraded forest fragments and human-altered habitat within and surrounding the park in forest edges, regenerating secondary forests, active and abandoned agricultural areas, plantations, and pasture lands. This indicates a much greater degree of adaptability than previously thought possible for this hawk, at least as long as an adequate prey base persists.

Food and Feeding Behavior: Feeds mostly on snakes and lizards (skinks and anoles) and less commonly on small birds and mammals. A recent study of 20 nesting pairs by Lance Woolaver in the Los Haitises National Park showed that reptiles comprised 97% of the prey items, and a few rats and birds were also taken. No domestic poultry were among the prey items, despite the close proximity of occupied houses near some nests, and conviction by local residents that this species is a threat to their chickens. (R. Thorstrom in litt.).

Breeding: Display flights begin in January, occurring most often between 1000-1200 h, and nest building, done mostly by the male, begins in late February (Wiley and Wiley 1981, Woolaver 2011). The nest is a platform of sticks placed high in a tree or palm in dense vegetation. Clutch size is 1-3 eggs (usually 2), which are chalky cream and heavily marked with orange-red mottling. The female performs most of the incubation, but both sexes participate in nest defense. Males captured 91% of prey brought to the three nests studied by Wiley and Wiley (1981). more....

Conservation: The Ridgway's Hawk has been declining since the late 19th century. It was extirpated from Haiti and its outlying islands (Keith et al. 2003) and is now limited mostly to the Los Haitises National Park in the Dominican Republic. The main cause of the decline of this species appears to be the loss of forested habitat through clear-cutting and burning for agriculture and also persecution by the local human population, especially at nests (e.g., Thorstrom et al. 2005, Woolaver 2011). This species is categorized as Critically Endangered by BirdLife International (2007).more....

Population Estimates: Thorstom et al. (2007) estimated the total population at 200-250 individuals, based on their studies between 2002-2005.

Important References: 
Collar, N.J., L.P. Gonzaga, N. Krabbe, A. Madrońo Nieto, L.G. Naranjo,
  T.A. Parker, III, and D.C. Wege.
1992. Threatened birds of the America: the
  ICBP/IUCN Red Data Book. International Council for Bird Preservation,
  Cambridge, UK.
Thorstrom, R., J. Almonte, and S. Balbuena de la Rosa. 2007. Current
  status and breeding biology of the Ridgway's Hawk. Pp. 33-39 in K.L
  Bildstein, D.R. Barber, and A. Zimmerman (eds.), Neotropical raptors. Hawk
  Mountain Sanctuary, Orwigsburg, PA.
Thorstrom, R., J. Almonte, S. Balbuena de la Rosa, P. Rodríguez, and E.
  Fernández.
2005. Surveys and breeding biology of Buteo ridgwayi
  (Ridgway's Hawk) in Los Haitises, Dominican Republic. Caribbean Journal of
  Science 41:864-869.
Wiley, J.W. 1986. Status and conservation of raptors in the West Indies.
  Birds of Prey Bulletin 3:57-70.
Wiley, J.W., and B.N. Wiley. 1981. Breeding season ecology and behavior of
  Ridgway's Hawk (Buteo ridgwayi). Condor 83:132-151.
Woolaver,L.G., Jr. 2011. Ecology and conservation genetics of Ridgway's
  Hawk Buteo ridgwayi. Ph.D. dissertation, York University, Toronto, Ontario,
  Canada. 291 pp.
more....

Current Research: Since 2002, The Peregrine Fund has been coordinating surveys of Ridgway's Hawks in the Dominican Republic under the direction of Russell Thorstom and in collaboration with the Hispaniola Ornithological Society (SOH) and Fundación Moscoso Puello, Inc. The field team, headed by Jesús Almonte and Samuel Balbuena de la Rosa, has worked mainly in Los Haitises National Park, the last known stronghold for the species, and has also searched for Ridgway's Hawks in other areas in the Dominican Republic, especially in the southwest region near Sierra Bahoruco National Park. In addition, a translocation program has involved releases of juveniles on privately owned lands at Loma La Herradura (about 30 km E of Los Haitises) and Punta Cana (130 km SE of Los Haitises).

Sites of Interest:
The Peregrine Fund
Field studies in the Dominican Republic.
BirdLife International
Information on current status and recommended conservation actions.

Researchers:
Thorstrom, Russell
Wiley, James

Last modified: 9/3/2011

Recommended Citation: Global Raptor Information Network. 2014. Species account: Ridgway's Hawk Buteo ridgwayi. Downloaded from http://www.globalraptors.org on 14 Sep. 2014








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