Justification of Red List Category
This species is classified as Endangered because it has a very small, fragmented and declining breeding range and population. It has already been extirpated from some sites, and declines are likely to continue as a result of habitat loss and degradation, hunting and invasive predators.
The population is estimated as no more than 1,000 breeding pairs, perhaps as few as 500, and a total population of 2,000–4,000 birds.
The population undoubtedly declined through the 19th and 20th centuries during which time breeding populations on Guadeloupe, Dominica and Martinique may have been entirely extirpated. This decline is thought to have continued during recent years but requires confirmation.
Pterodroma hasitata is confirmed as breeding in Hispaniola (comprising the nations of Haiti and the Dominican Republic). The population there is estimated as no more than 1,000 breeding pairs, perhaps as few as 500, and a total population of 2,000–4,000 birds. The highest density of nests and most of the population occurs on La Visite Ridge in the western extent of the Massif de la Selle, Haiti. Smaller populations occur eastward along the Massif de la Selle and across the border in the Sierra de Bahoruco of the Dominican Republic, as well as around Pic Macaya in Massif de la Hotte in western Haiti. Radar surveys and aural observations indicate that small populations occur in other areas to the north and east in the Dominican Republic but nests have yet to be located (E. Rupp in litt.) Taking into account each of these known and suspected breeding sites, all of which are quite small, an area of occurrence estimate of 20 km2 is reasonable (E. Rupp in litt.).
Radar surveys conducted in Dominica in January 2015 strongly suggest that Black-capped Petrels persist there; hundreds of petrel-like targets were recorded over 17 separate coastal and inland flight corridors, and eight individual Black-capped Petrels were observed over 5 locations (Brown 2015). These data, when coupled with recent observations of downed Black-capped Petrels on the island, suggests that there are still individuals breeding on the island, although the last confirmed nesting date was 1862.
Black-capped Petrels previously nested on Guadeloupe and Martinique, but have not been documented there since before 1900. However, hope persists for rediscovery on Guadeloupe (A. Chabrolle in litt.) based on offshore observations and the presence of inaccessible island peaks. Likewise, hope persists for Cuba. Though there is no documentation of Black-capped Petrels nesting in Cuba in the past or currently, there have been observations of birds flying inland at dusk from a known foraging area.
Black-capped Petrels are highly pelagic and undertake long-distance foraging trips. A compendium of about 5,000 at-sea observations indicates that waters in or adjacent to the Florida Current and the Gulf Stream between northern Florida and southern Virginia provide a distinct and relatively confined foraging range of Black-capped Petrels, with concentrations observed there throughout the year. In the Caribbean Sea, Black-capped Petrels can occur within the inter-island regions, straits and offshore zones of both the Greater and Lesser Antilles, but still primarily east of 80°W. The first satellite tracking of this species (three individuals) suggest a similar, but more spatially expansive range, including regular occurrence in the Caribbean Sea between Hispaniola and South America and regular occurrence east of primary foraging area indicated by the at-sea observations (Jodice et al. 2015).
Field investigations on Hispaniola suggest that Black-capped Petrels lay eggs in mid- to late January, chicks hatch in mid- to late March and fledglings depart the colony sites in mid-June to early July (Simons et al. 2013). All nests located to date are at high elevations (>1,500 m), and while most are in inaccessible areas (steep slopes, heavily forested) some are not (E. Rupp, in litt.). Nesting success from monitoring over 4 years was 70-77% (n = 47 nests) with abandonment and predation causing most failures (E. Rupp, in litt.)
Nesting birds commute long distances from breeding to foraging sites, typically feeding in flocks. It is primarily nocturnal and crepuscular, feeding on squid, fish, crustaceans, and Sargassum. In its primary foraging range, the Black-capped Petrel is most influenced by the position of the Gulf Stream, a dynamic current system, and not sea surface temperature or depth. (Simons et al. 2013).
The increased frequency of fires represents a significant threat to the Black-capped Petrel through habitat loss, degradation and direct mortality. Fires and electric lights can cause the birds to become confused and disorientated causing mortality through collisions or grounding of the birds (Wingate 1964). Once grounded, many birds are unable to regain flight, leaving them vulnerable to predation and starvation. A number of electric communication towers are located on mountaintops close to petrel breeding grounds and are often stabilised with multiple guy wires and well lit (Goetz et al. 2012). These towers appear to be a considerable source of mortality, with a two-night investigation in 2013 finding several dead and grounded birds below a single tower, as well as hearing birds hitting the guy wires (A. Brown in litt. 2013). Mitigation efforts are in place for some towers and have greatly reduced the impact at these locations however further towers require investigation and modification (A. Brown in litt. 2013).
Small-holder farming, cattle ranching and logging for charcoal are all significant sources of habitat loss, despite being illegal within the forests of Sierra De Baoruco National Park in the Dominican Republic (BirdLife International 2016). Rats and Feral cats are abundant at all known Black-capped Petrel breeding locations and, although their current impact on the species is unknown, in other ecologically similar petrels these species are responsible for nest failure and fledgling and adult mortality (Goetz et al. 2012). Dogs, pigs and mongoose may also predate the species. Direct consumption by humans is implicated in the extirpation of Black-capped Petrel on Martinique and Guadeloupe (Lee 2000), and this intentional use is ongoing in other areas. The gathering of terrestrial plants across the Black-capped Petrel’s range is not thought to cause significant declines.
Mercury concentrations in tissues from specimens of the species were found to be considerably higher than in other species studied (Whaling et al. 1980, Simons et al. 2013) but impacts are unclear and likely restricted to lowered reproductive success rather than direct mortality.
Conservation Actions Underway
An International Black-capped Petrel Conservation Group has formed and facilitates communication and coordination among researchers and conservationists concerned about the species. Partners have greatly advanced understanding of occurrence, abundance, threats, and breeding ecology and continue to undertake research as they embark on conservation strategies to reduce threats. Community engagement to improve socioeconomic conditions and reduce unsustainable agriculture is underway adjacent to nesting sites on the Haitian-Dominican Republic border (IBCPCG 2016).
Conservation Actions Proposed
Develop and undertake conservation strategies to halt encroachment in Haiti and improve park management (e.g. fire control) in Haiti and the Dominican Republic. Continue surveys to determine distribution on Hispaniola, Dominica and at-sea and to determine presence on Cuba, Jamaica and Guadeloupe. Research key threats in order to reduce and/or mitigate them, and monitor population status throughout range (Goetz et al. 2012).
40 cm. Medium-sized, long-winged gadfly petrel. Brownish-black cap extending to eye, nape and towards upper breast where forms partial collar. White hindneck. Brownish-grey mantle and upperwing. White rump and uppertail-coverts. Dark brown tail. Entirely white underparts. White underwing with narrow black trailing edge, black tip, broad black edge between primaries and carpal joint. Band extends weakly towards centre of wing from joint. Black bill. Pink legs, and feet pink proximally, black distally. Similar spp. Bermuda Petrel P. cahow is smaller and usually lacks white hindneck and rump, but separation may sometimes be impossible. Great Shearwater Puffinus gravis is larger, darker and less contrasting above, lacks black edge to underwing and has slower wingbeats and less erratic flight.
Text account compilers
Isherwood, I., Mahood, S., Martin, R., Moreno, R., Stuart, A., Sullivan, B., Wege, D., Wheeler , J., Benstead, P., Bird, J., Anderson, O., Butchart, S., Clay, R.P., Fjagesund, T., Hermes, C.
Feldmann, P., Wheeler , J., Fernandez, E., Brown, A., Gerwin, J., Demarest, D., Wallace, G., Lee, D., Goetz, J., Villard, P., Levesque, A., Rupp, E., Simons, T.
BirdLife International (2021) Species factsheet: Pterodroma hasitata. Downloaded from http://www.birdlife.org on 25/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/10/2021.