|Director of Conservation Biology, Vermont Institute of Natural Science|
|Demographics, Breeding Biology, and Conservation of Hispaniolan Birds|
|Location: Sierra de Bahoruco of the Dominican Republic|
|Species: Hispaniolan Birds|
|Abstract: This study is in the final year of its pioneering 3-year study of the breeding ecology of avian communities in Sierra de Bahoruco of the Dominican Republic. This study will collect crucial biological knowledge on a group of birds that includes many endemic species, several of which are threatened with extinction due to severe, ongoing habitat loss. Through the project's first two years, detailed data has been collected on more than 600 individual nests in four distinct habitats over an elevational gradient of nearly 2,000 meters. During the 2004 breeding season, this research will expand investigations of the demographic structure, habitat associations, and breeding biology of Hispaniolan resident bird species, to measure productivity and survival among nesting birds, to expand avian monitoring programs in the Sierra de Bahoruco, to conduct intensive field training of Dominicans, and to provide a database for sound management and conservation. Demographic data will be combined with habitat relationship data to examine factors or events that may regulate populations. Two teams of Dominican biologists will conduct the majority of field work; training and capacity building of these biologists is a vital component of this project.|
Project Report: January 2007
This report summarizes findings from the final year of a three-year study to investigate the breeding ecology and habitat associations of Hispaniolan resident bird species in Sierra de Bahoruco of the southwestern Dominican Republic. This research, the first of its kind in the Caribbean Basin, will provide the biological data necessary for important management and conservation decisions. Fieldwork in 2004 began in early March, and was conducted by a team of 4 experienced Dominican ornithologists and 2 Dominican trainees. The project's 7 study sites consisted of 2 in coastal thorn scrub habitat [desert], 2 in mid-elevation dry forest, 2 in high elevation pine forest, and 1 in montane broadleaf forest. Nest searching in the three lower elevation habitats was initiated during mid-March. Wet weather in April stimulated a flush of breeding, and many nests in the desert sites were located during April and May. Fieldwork at the montane broadleaf site began in early May, accounting for the later avian breeding phenology at high elevations. Field work was completed at all sites by 1 August.
The study's final year was its most successful, with 549 nests of 41 species found in total. As in the preceding two years, the desert sites yielded the greatest number of nests with 330 found, while 159 nests were found in the two broadleaf habitats combined, and 60 in pine forest habitat. Success rates were similar to those documented in the study's first two years. Of 511 nests with known outcomes, only 230 (45%) successfully fledged at least one chick. Nest success varied considerably among species (e.g., 67% in Common Ground Dove, 40% in Hispaniolan Emerald, 19% in Northern Mockingbird), but less so among habitat types. Most failed nests were lost to depredation.
Two exciting highlights in 2004 involved the first nests known to science of Western Chat-Tanager and White-winged Warbler, both rare and globally vulnerable endemic species restricted to montane broadleaf forests on Hispaniola. The Chat-Tanager nest was unfortunately depredated during the nestling stage, while the warbler nest fledged a single chick. Detailed descriptions of both nests have been submitted for publication to the Wilson Bulletin.
The laborious process of entering the detailed data for each nest (>1200 during the 3 years) has been completed, error-checking is nearly complete, and preliminary analyses are underway. We are confident that the information gained from this study will yield important insights about the ecology, demography, and limiting factors of Hispaniolan breeding birds. This information will be used to guide further studies and develop conservation plans.
Table 1. Nest totals by species in each habitat, 2004