In the West Indies, there are several forest birds of prey that are considered rare or endangered: the Grenada Hook-billed Kite, Cuban Kite, Gundlach’s Hawk, and Ridgway’s Hawk.
The Ridgway’s Hawk is an endemic species to Hispaniola. Formerly found throughout the Dominican Republic and Haiti, and on other satellite islands, populations have declined due to habitat loss and persecution. The last few individuals are currently found in Los Haitises National Park, northeastern Dominican Republic. The endangered Cuban Kite and Gundlach’s Hawk, found in Cuba, have also been severely reduced in numbers. The Grenada Hook-billed Kite is an endemic subspecies that was considered at one time extinct but is currently regarded as endangered. A few pairs have been found in this small island.
Little is known about these four Caribbean raptor species. The most significant studies on the Ridgway’s Hawk are from 1976 and 2005-2009. The most important reasons for their declines are not fully understood. Studies on these species will provide critical information that may help in the development of more effective conservation plans and training of personnel.
The West Indies Project is providing the only known conservation effort to save threatened birds of prey in the Caribbean region, currently with a special focus on the critically endangered Ridgway’s Hawk. Historically, the Ridgway’s Hawk was found throughout the Caribbean island of Hispaniola, which includes the countries of Dominican Republic and Haiti. The Peregrine Fund began studying this critically endangered raptor in 2000 and found the hawks to be breeding only in Los Haitises National Park (LHNP) in the northeastern Dominican Republic. We have thoroughly searched, surveyed, and monitored this population and determined that only about 300 individual birds comprise the entire global population of this species.
This small and isolated population of Ridgway’s Hawks leaves the species extremely vulnerable to extinction through catastrophic events such as fire, hurricane, or disease. To reduce this risk, in 2008 we began an experimental “assisted dispersal” project to learn if breeding pairs could be reestablished in the species’ former range outside of LHNP. Young birds were collected from nests near the Los Limones community of southwestern LHNP about one week prior to fledging age. They were fed in a hack box (a protective aviary) at the release site until fledging age, and then released by removing the bars on the front side of the box. The fledged birds were fed daily at the box for several months until they reached independence.
The first release in 2008 successfully fledged four young hawks at Loma la Herradura (40 miles south of LHNP) on private land owned by Central Romana Corporation, Ltd., the largest company in Dominican Republic. This site was used again in 2009 and a second release site was established at Grupo PuntaCana (100 miles southeast of LHNP), a private resort and land holding company.
In all, 39 Ridgway’s Hawks have been released; 19 in Grupo PuntaCana and 20 at Loma la Herradura. We continue to monitor 6 individuals in Grupo PuntaCana and 2 in Loma la Herradura. In 2013, the first pair of hawks documented outside of Los Haitises was observed in Grupo PuntaCana in March. The male and female of this pair had been released in 2010 and 2011, respectively. This pair successfully fledged one young.
We surveyed for critically endangered Ridgway’s Hawk in Los Haitises National Park in eastern Dominican Republic and observed a total of 109 pairs and 17 individuals. Of these, 51 pairs were monitored extensively by the field crew in Los Limones. Of the 51 pairs monitored in Los Limones, 46 were observed incubating eggs. Twenty-nine of these 46 nests were successful in producing at least one fledgling. In all, 60 nestlings were recorded and a total of 50 were recorded as fledging. Forty-nine (only 44 fledged) of these nestlings were banded and 20 adults were trapped and banded or re-banded with a legible band.
High nest success can be attributed to treating 48 of the 60 nestlings either to prevent or cure botfly parasitism by Philornis pici. Botfly infestations and human persecution were identified as the main causes for the nestling mortality. Field biologists worked with veterinarians from the Santo Domingo Zoo to improve methods for treating nestlings using Frontline Spray (fipronil). Nests that were climbed were also reinforced as needed to prevent loss of nestlings to falling nests. Two new field technicians were trained in Los Limones; one of these techs was trained specifically to climb nests. In addition, two nestlings were banded and treated for parasites near Cano Hondo on the eastern side of LHNP and two chicks were treated for parasites near Laguna Cristal on the northwestern side of LHNP.
In Grupo PuntaCana, three hawks from previous releases were trapped and their transmitters were replaced. We attempted to trap two additional hawks without success. The first nesting pair was recorded this year in Grupo PuntaCana and ultimately ended in a successful nesting, producing one offspring. This nestling was ultimately banded and also received a transmitter. In Loma la Herradura, we attempted to trap two hawks without success. Trips were taken to three areas outside of LHNP to search for Ridgway’s Hawks and or potential release sites. The Samana Peninsula, Parque del Este and Parque Nacional Valle Nuevo were all visited. No Ridgway’s Hawks were recorded.
We visited a total of 11 different communities and reached more than 850 individuals in the area around the Grupo PuntaCana release site. Educational activities included door-to-door visits, PowerPoint presentations, school presentations, and live bird demonstrations. Surveys were also conducted to measure individual levels of knowledge about the Ridgway's Hawk and other raptors, as well as to measure their attitudes toward these birds and conservation in general. These surveys will be used as a basis for future evaluation of the education program's efficacy and will allow us to make improvements in our educational strategies as necessary.
Developing Local Capacity Through Training
In Dominican Republic, we are developing local capacity for raptor conservation by supporting and training local biological field assistants. Biologists from TPF and veteran field technician Samuel Balbuena de la Rosa have provided biodiversity and conservation training to several park guards and local persons from communities bordering the park, especially in the Los Limones area. We began training three more field technicians. Two of these new technicians are from Los Limones and one from Trepada Alta. One of these newly trained assistants was trained to climb palm trees for nest monitoring. This type of training of locals will ensure that the capacity exists to monitor and manage raptor populations into the future.
Another side effect of training locals to work in conservation is the stimulation of local economies. Having community members earning their income from conservation has also proven to be an effective way of changing people’s attitudes towards raptors and conservation. In addition to monitoring the wild population of Ridgway’s Hawks, assistants have helped conduct the assisted dispersal releases of young Ridgway’s Hawks on private and protected land holdings owned by Central Romana Corporation, Ltd., the largest national company in Dominican Republic, and Grupo PuntaCana.
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