Black-capped Petrel (Pterodroma hasitata)

Taxonomy

Monotypic
Also known as Diablotin or Capped Petrel.
 

Identification


Ventral view of Black-capped Petrel off Cape Hatteras, North Carolina in August 1996. Copyright Angus Wilson©.

A relatively large and distinctive gadfly petrel. Larger and more robust than Bermuda Petrel. As its name suggests, has a clearly defined cap, separated from the dark mantle by a weak white collar. Conspicuous white 'rump' (uppertail coverts) forming a broad 'U' shape. Distinctive black and white underwing pattern, comprising a broad black trailing edge and diagonal black bar across the secondary coverts. Throat and underparts snowy white. Darker upperparts intrude at the shoulder, forming a weak half collar.

Flight dynamic and typical of gadfly petrels. In winds greater than 10 knots, adopts a sinusoidal motion, one wing pointed at the water, the other at the sky. Does not follow ships but may swing by (at great speed) to investigate a potential source of food. May form small rafts during the day, flushing away from the approaching boat.


Videograb of a Black-capped Petrel off Cape Hatteras, North Carolina in May 2001. Copyright Angus Wilson© 2001
 

Where and When

Nests during the northern winter on forested slopes and cliffsides on Hispaniola in the Caribbean, an possible neighbouring islands. A colony was relocated at Lomo de Toro, Dominican Republic in April 1996 (Williams et al., 1996), the first breeding record in country since 1981. With luck, other colonies await discovery. The Hispaniola population was estimated at more than 4000 in 1961 (Wingate, 1964). With increased conservation measures, the species may be recovering slightly. Click here to view a range map for the Caribbean and central America.

During the 1980's and 90's it became clear that this species is locally abundant in the Gulf Stream waters off the US mid-Atlantic states, frequenting waters 400m or deeper (Brinkley and Patteson, 1998). Recorded on most pelgic trips out of Oregon Inlet or Hatteras, North Carolina. Largest numbers occur during mid summer and early fall and comprise birds in a variety of plumage states. In late fall (mid-Oct), the adults begin to return to breeding areas. Mated birds (primarily females) return to the Gulf Stream during December to feed and fatten before the eggs are laid. A few (nonbreeders?) remain in the Gulf Stream during January to April. Much rarer within the Gulf of Mexico. Hurricanes regularly blow birds inland, some even reaching the Great Lakes.
 

Photographs on the web

Three birds in flightTaken in Gulf of Mexico off Texas. Photos by Michael Gray and Phyllis Frank.
 
 

Literature

Brinkley, ES. (1996) Secrets of the Deep. Birdwatchers Digest 18(6): p66-72

Brinkley, ES. and Patteson, JB. (1998) Gadfly Petrels in the western North Atlantic. Birding World 11(9): p341-354.

Haney, JC. (1987) Aspects of the pelagic ecology and behavior of the Black-capped Petrel. (Pterodroma hasitata). Wilson Bulletin Vol? p153-167.

Williams, R. S. R., et al. (1996) The status of the Black-capped Petrel Pterodroma hasitata in the Dominican Republic. Cotinga 6: 29-30.

Wingate, DB. (1964) Discovery of breeding Black-capped Petrels on Hispaniola. Auk 81: p147-159.



Copyright © 2002 All rights reserved. Angus Wilson
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