Buteo ridgwayi

The Dominican Republic is home to 30 species of birds found nowhere else in the world. Unfortunately, 19 of these are in danger of becoming extinct.  As forest is cut down to produce charcoal or create more farmland, there is less and less habitat for these birds. Today, less than 10 percent of the native forest remains.

Our 2004 Canadian Collection recipient and former Canada’s New Noah, Lance Woolaver, studied the ecology, distribution and breeding biology of seven of these rare species within the Sierra de Bahoruco and Los Haitises National Parks.  As part of a three-year PhD. research project, he looked at the baybreasted cuckoo, hispaniolan parakeet, hispaniolan parrot, plain pigeon, grey-headed quail-dove, white-necked crow and Bicknell’s thrush.  However, his top priority was the critically endangered Ridgway’s hawk.

Lance and his wife, Rina Nichols, monitored six pairs in Los Haitises National Park throughout the 2004 breeding season with the help of six local biologists. This was the first time that nests had been monitored since the species became endangered.  All six pairs tried to nest, but didn’t succeed at fledging any young.  Three nests failed during incubation, and three after hatching.

In 2005, Lance monitored 22 nests and collected DNA samples from adult birds to determine the degree of inbreeding and loss of genetic variation in this very small remnant population.  Adult and juveniles were colour banded for long term monitoring, and a community education program was launched to make local people aware of how rare and unique this hawk is.

Learning the basic biology of a rare species – nesting, feeding and breeding – is key to helping conserve it.  And once we know more about it – what its ecological needs are, and why the population is declining – then we can determine what needs to be done to help the species rebound, and put that into action.

Description

This small, elegant forest raptor is the most endangered hawk in the Caribbean.  It is brownish-grey on top and grey underneath, with a black and white barred tail.  Males also have reddish thighs. On average, Ridgway’s hawks measure between 36 and 41 cm long, and females are somewhat larger than males.

Habitat

Ridgway’s hawks live in undisturbed forest, feeding on small mammals, birds, lizards and snakes and nesting in the crown of tall trees.

Distribution and Population Size

These hawks were once widespread throughout the Dominican Republic and Haiti.  In the Dominican Republic, they are now restricted to an area of just 120 square kilometres in the lowland rainforests of Los Haitises National Park.  There have been very few recent sightings outside this area.  Today, there are fewer than 50 hawks.

Threats to Survival

The Ridgway’s hawk faces two main threats: pressure to convert the national park into agricultural land, which would destroy its vital habitat, and the risk of being shot by local people.