A critically rare and local breeder in the Caribbean, with populations known to nest in Haiti and Dominican Republic. Black-capped Petrel also recently was rediscovered breeding on Dominica, where breeding last had been confirmed in the late 19th century (Collar et al. 1992). Formerly also bred on Guadeloupe, though now apparently extirpated there (Collar et al. 1992), and may have nested on Martinique, although no strong recent evidence (Lee 2000). There are an estimated 1,000 breeding pairs, mostly in the Massifs de la Selle and de la Hotte, southern Haiti, but records at-sea suggest that the population is over 5,000 individuals. The area of suitable habitat in the Pic Macaya region of Massif de la Hotte is estimated to be several km2, with a similar area in La Visite, Massif de la Selle (the majority of colonies formerly found within a 10 km stretch spanning a 500 m elevational range on the north side of the ridge, though now reduced to smaller area of forest, more so since the 2010 earthquake; two more colonies are located further to the east, span 5 km, again within a 500 m elevation range, Simons et al. 2006). Even during the breeding season it is highly pelagic, with breeding condition birds recorded off the North Carolina coast, USA.
Birds disperse over the Caribbean and Atlantic from the north-east USA to north-east Brazil, but the at-sea range has contracted in the north and west. Occasionally birds are entrained in hurricanes and deposited far inland - for example, Hurricane Fran displaced what was probably many tens of Black-capped Petrels into the Great Lakes in the Northeastern US. Generally, in temperate summer months of June-September, Black-capped Petrel frequents the western edge of the Gulf Stream.
Cornell Lab of Ornithology conducted a Rapid Biological Inventory at Parque Nacional La Bayamesa, Cuba, in February 2004, and this included a survey for Black-capped Petrels. N. Viña led the team to a site along the coast near Uvero, a remote location directly below Pico Turquino and near a location of previous site records of the species (Farnsworth et al. 2005). The team found petrels on two occasions: 25 birds on 9 February 2004 and up to 46 Black-capped Petrels on 24 February. Birds were flying within 50 meters, at times, of the bluffs, forming several tight flocks on the water just offshore. After dark, vocalizations from the birds indicated that at least some of the petrels flew ashore and up a stream valley and steep mountainside towards the Sierra Maestra peaks. Forsell (U.S. Fish and Wildlife Service, pers. comm.) commented that ‘Petrels don't go up into mountains or hang around shores unless they are breeding and I would consider that confirmed. Most petrels and shearwaters go ashore at dusk or in the dark and leave before first light. I would consider flocks of birds sitting on the nearshore waters at dusk a sure thing, but seeing or hearing them calling going ashore as good as finding a nest.’