Courtesy Kenn Kaufman
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.