(c) Glen Tepke
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Holding its wings in a sickle shape and flying erratically in heavy winds, the Black-capped Petrel is typical of the gadfly petrels. On its breeding grounds in the Caribbean, its haunting nocturnal calls earned it the nickname Diablotin, the "little devil." Once fairly common, the Black-capped Petrel is drifting toward extinction. Observers almost never see it from shore, but find it regularly off North Carolina's Outer Banks.
A medium-sized seabird, Black-capped Petrels are known for their rolling and agile flight at sea. Adults are mostly white underneath, and dark brown to black on the back and upper wings. As signified by their name, these seabirds have a black "cap" and white collar behind the head. The collar, and their conspicuous white rump can help to separate them from the similar-looking Bermuda Petrel and Jamaican Petrel (now believed to be extinct). The long, pointed wings are usually bent, and the tail is wedge-shaped. Black-capped Petrels measure about 16 inches long with a 38 inch wingspan.
In summer, the Black-capped Petrel is found at sea from northeastern South America to the eastern U.S., where it frequents the western edge of the Gulf Stream. Currently, the only known breeding colonies are located in the highlands of Hispaniola - on Massif de la Selle and Massif de la Hotte in Haiti and in the nearby Loma del Toro in the Dominican Republic. Some researchers believe that other breeding colonies are not yet accounted for. Evidence suggests a small population breeds in Cuba. Likewise, reports from Dominica have not yet been followed by the discovery of other nesting sites. The Black-capped Petrel has been extirpated from much of its previous breeding range.
Black-capped Petrels live at sea during the non-breeding season, returning to their nesting sites from December to April, although birds have been reported at these locations as early as August. The species feeds along the edges of the Gulf Stream primarily in areas where deep, nutrient-rich ocean waters are forced to the surface and produce concentrations of squid, fish, and crustaceans. More specifically, the Black-capped Petrel seems to associate with Sargassum and Gulf Stream eddies. On fairly large islands in the Caribbean, all known colonies are found in forested mountain slopes at elevations between 4,900 and 7,500 feet above sea level.
Foraging seems concentrated at dawn, dusk, and night. Most food is captured in flight by seizing items with the bill. This petrel has also been observed touching the ocean surface with its feet (pattering). More rarely, it sits on the water with wings held high and sometimes dips its head below the surface. The diet appears to consist of squid and warm water fish like the planehead filefish (
Monocanthus hispidis) and flying fish. This species often feeds where predators like blue-fin tuna push small species to the surface. It forages alone or in small flocks of shearwaters, petrels, and other seabirds. Discarded fish oil and parts (chum) sometimes attract it to boats. Waste petroleum oil, paper, and plastics have been found in the stomachs of the Black-capped Petrel.
Like so much of its ecology, the breeding habits of this petrel are poorly described. In early November, Black-capped Petrels assemble off the shores of their nesting islands. The petrels approach their colony at night with bizarre calls, described as cries or screams. They excavate burrows in the soil or use natural fissures in rock outcroppings as nesting sites. In a burrow about 3 feet long, one male was observed sitting on an empty nest, constructed of sticks and pine needles. This burrow appeared to have been used in previous years. Young Black-capped Petrels probably fledge between late May and early June.
After breeding, most Black-capped Petrels disperse into the Atlantic Gulf stream from Florida to New England (far offshore). A few petrels appear to stay near the Caribbean and have been sighted near the northeastern coast of South America.
BirdLife International. "
Species factsheet: Pterodroma hasitata." 2007. Accessed 15 June 2007.
Haney, J. Christopher. "Aspects of the Pelagic Ecology and Behavior of the Black-capped Petrel
(
Pterodroma hasitata)." The Wilson Bulletin 99:2 (June 1987) 153-168.
Onley, Derek and Paul Scofield.
Albatrosses, Petrels and Shearwaters of the World. Princeton and Oxford: Princeton University Press, 2007.
Simons, Theodore R. Jaimie Collazo, John Lee, and John Gerwin. "
Conservation Status of Black-capped Petrel (Pterodroma hasitata): Colony surveys at Sierra de Baoruco, Dominican Republic, January 2002." December 2002. Unpubl. report, North Carolina State University, Raleigh, NC. Accessed 15 June 2007.
