Cooperative Fish and Wildlife Research Units Program: North Carolina
Education, Research and Technical Assistance for Managing Our Natural Resources

Simons, T.R., D.S. Lee, and J.C. Haney. 2013. Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel. Marine Ornithology 41(Special Issue): 1-43.


The Black-capped Petrel (Pterodroma hasitata) was believed extinct throughout much of the twentieth century. It is the only gadfly petrel currently known to breed in the Caribbean Basin. Now seriously endangered, the species has been extirpated from Martinique, Dominica, and Guadeloupe and breeding populations currently occur only on Hispaniola and perhaps Cuba A related form (now considered a full species) once bred, but is now apparently extinct, on Jamaica. The Black-capped Petrel breeding population may number as few as 500 breeding pairs. Remaining populations suffer from multiple threats to terrestrial and pelagic habitats, harvest by humans, and predation by introduced mammals. The exact sizes, locations, and detailed chronologies of all Black-capped Petrel breeding sites remain poorly-studied, although major colonies are today apparently restricted to steep sea and inland cliffs along the La Selle Ridge in Hispanolia. The largest known breeding population occurs in Haiti, although there is continued discussion about a possible breeding site in Cuba in the Sierra Maestra mountain range. Accounts from Cuba are based on the unverified assumption that birds observed at sea just offshore of that island are breeding locally. All evidence at present indicates that waters in or adjacent to the Florida Current and the Gulf Stream between north Florida and southern Virginia provide the primary foraging range of Black-capped Petrels. A small foraging area just off of SE Cuba has also been reported, but the extent and seasonal use of this area are unknown. Concentrations of birds can be found along the Gulf Stream in southeastern U.S. waters throughout the year, where the birds are particularly common in May, August, and late December through early January. Concentrations of adult birds during winter, when peak breeding activity is underway, suggest that breeding birds forage along the Gulf Stream while commuting to and from breeding colonies. Such long-distance foraging is certainly possible for species of the Genus Pterodroma. Potential threats to Black-capped Petrels include introduced predators, human encroachment on breeding and foraging habitats, and offshore oil, gas, and wind energy development. Increased mercury levels associated with petroleum production also pose a potential threat, as the Black-capped Petrel seems to be highly susceptible to mercury bioaccumulation compared to other pelagic species. In addition, fires and other bright light sources are known to attract Black-capped Petrels, making collisions with wires and other structures on lighted ships and platforms a potential concern. Haitian social-economic instability and increasing habitat loss suggest the likelihood of further population declines and increasing vulnerability of the species to extinction. Our findings are in accord with the recent decision by the USFWS to evaluate the need for additional protection of the species and the primary foraging habitat off of the SE United States under the Endangered Species Act (USFWS 2012). Additional conservation measures and research strategies that warrant further consideration include, (1) protection, monitoring, and management of known breeding populations and nesting habitat in the Dominican Republic and Haiti through predator control, the installation of artificial nest burrows in appropriate sites, and hiring local wardens at breeding sites during the nesting season, (2) local and regional training, education, and public awareness (e.g., Blanchard and Nettleship 1992), and (3) restoration of the original name ‘Diablotin’ for standard usage to promote the historical and cultural importance of this species, (4) studies to determine the distribution and genetic variability in the remaining populations and; (5) studies of satellite-tagged birds to assess their seasonal and geographic use of pelagic habitats.