About Pterodroma hasitata (Kuhl, 1820)
The black-capped petrel (Pterodroma hasitata) is a large gadfly petrel, measuring about 16 inches (40.5 cm) long with a 37-inch (94 cm) wingspan. Within its range, the species that most resembles it is the smaller Bermuda petrel, which has a narrower white rump patch and an extensive gray cowl. The great shearwater is also superficially similar. The critically endangered or possibly extinct Jamaica petrel (P. caribbaea) was a related dark form. Its local Spanish name, Diablotín, translates to "little devil". This name comes from its night-time habits and unusual mating calls, which led local people to believe evil spirits were present in the dark. Black-capped petrels will occasionally make other croaking sounds while foraging at sea. On their breeding grounds, black-capped petrels are nocturnal, possibly to avoid predation by gulls, hawks, or crows. Like most petrels, their walking ability is limited to a short shuffle to reach the nest burrow. This seabird once bred on steep mountainsides across the Greater Antilles, but only three confirmed breeding areas remain in the high mountains of Hispaniola: these are Sierra de Bahoruco and Valle Nuevo National Park in the Dominican Republic, and Massif de la Selle and Massif de la Hotte in Haiti. In 2015, nesting was also confirmed on Dominica, a second island where historical nesting had long been suspected. A mountain peak that this species formerly bred on in Haiti, as well as another in Dominica, are still named "Mont Diablotin" after the species' "little devil" nickname. The warm waters of the Gulf Stream are the primary foraging area for black-capped petrels. During the non-breeding season, most individuals are concentrated off the coast of the United States between Florida and North Carolina, though the species is known to wander far to the north and east toward Europe. Black-capped petrels can be seen in the Gulf Stream year-round. Birds that visit these waters during the breeding season are either non-breeding individuals or making long foraging trips away from their nests. Away from breeding grounds, the black-capped petrel is almost strictly pelagic, and it is known to join loose flocks with other seabirds such as shearwaters and terns.
