Ridgway's Hawk


Ridgway's Hawk close up
Ridgway's Hawk close up

Discription:
The Ridgway's Hawk is a medium-sized, with a 36–41 cm long wing span. This hawk is named after the ornithologist Robert Ridgway. The adult hawk has brown-grey upper feathers, grayish barred under feathers, and a black-and-white barred tail. This bird of prey feeds on small mammals, birds, lizards and snakes. It nests in the crowns of tall trees in Los Haitises National Park in the northeastern Dominican Republic, which is mostly covered by wet limestone forest. This bird is critically endangered due to clearance of its forest habitat and persecution by local farmers, who erroneously believe the species preys on domestic fowl, even though reptiles comprise up to 90% of its diet.


Hawk in habitat
Hawk in habitat

Scientific Info:
Intensive research of the species’ breeding ecology and conservation genetics are part of an ongoing study initiated in 2005, and annual surveys are conducted to monitor the population within the Park (53 active nests monitored in 2007). Ongoing DNA work is comparing the extent of genetic variation remaining in the current population with the historical population to determine if poor genetic diversity should be a concern for species recovery. Ongoing monitoring at Los Limones in the east of Los Haitises National Park shows a 5-10% annual decline in the number of individuals at this site, equating to a decline over ten years of 40-65%. Declines in the west of the park are expected to be continuing at a similar, although perhaps slower rate, hence overall rates of decline are perhaps best estimated to fall within the band 30-50% over ten years. However, forest clearance within the park boundary remains rapid with an annual loss of c.10-15%, thus careful monitoring is a priority and it may reveal that a higher rate of decline is occurring (Woolaver, 2007). Most closely related to B. lineatus (Wiley and Wiley 1981), from which it is probably derived, but also close to B. nitidus (= Asturina nitida), B. platypterus, and B. magnirostris. Some have suggested that the species in this group are closer to Leucopternis than to Buteo (Bierregaard 1994). Although this species appears to prefer undisturbed forest 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).



Artistic drawing of Ridgway's hawk
Artistic drawing of Ridgway's hawk





Quick Facts:
  • Kingdom: Animalia
    Phylum: Chordata
    Class: Aves
    Order: Falconiformes
    Family: Accipitridae
    Genus: Buteo

  • Hispaniolan Royal Palms, Roystonea hispaniolana, are particularly favored trees for nesting.

  • Nest-building occurs in January-March and eggs laid in February-April.

  • The hawk lays 2-3 eggs and pairs have successfully fledged three chicks, but more typically one or two.

  • This species occurs in the Dominican Republic and formerly in Haiti.

  • Reptiles comprise 97% of their prey items

  • Nest building is mostly done by the male, like most birds.




Buteo Ridgwayi in flight
Buteo Ridgwayi in flight

Links to other topics:
  • Like our own Endangered Species Act, there have been conservation attempts for the Ridgway's Hawk.

  • The biggest threat is one that is most common among the endangered species list, loss of habitat. There is a lot of pressure to convert the national park into agricultural land, which is it's natural habitat.

  • The Ridgway's Hawk belongs in the family of birds of prey, scientifically called falconiformes, that are theorized to have evolved from dinosaurs, more specific, raptors.










Diagram of wing comparison of birds of prey
external image 204px-RaptorialSilhouettes.svg.png

Quick Videos:
http://www.arkive.org/ridgways-hawk/buteo-ridgwayi/video-00.html
http://www.arkive.org/ridgways-hawk/buteo-ridgwayi/video-09c.html





On the menu: spotted lizzard
On the menu: spotted lizzard

Bibliography:
Wikipedia: the free encyclopedia. 2011. 3/9/2011. http://en.wikipedia.org/wiki/Ridgway%27s_Hawk
BirdLife International (2011) Species factsheet: Buteo ridgwayi. 09/03/2011. 3/9/2011.
Global Raptor Information Network. 2011. 3/16/2011. Species account: Ridgway's Hawk Buteo ridgwayi. http://www.globalraptors.org