At a Glance

At one time, this bird was known in North America only from scattered waifs blown inland by hurricanes. Now it is known to occur regularly in the Gulf Stream, far offshore from the southeastern states. It breeds only in the West Indies, and has disappeared from most former nesting areas; should be considered at risk of extinction.
Category
Gull-like Birds, Shearwaters and Petrels
Conservation
Endangered
Habitat
Open Ocean
Region
Florida, Mid Atlantic, Southeast
Behavior
Flap/Glide, Soaring
Population
5.000

Range & Identification

Migration & Range Maps

Waters of Gulf Stream far off southeastern United States seem to be the main non-breeding distribution of this species. Some are present in these waters at all seasons; apparently most numerous (and farthest north) during the warmer months.

Description

14-18" (36-46 cm). W. 37" (94 cm). Flies fast, with deceptively slow wingbeats, long glides, high arcs. Pattern suggests Greater Shearwater, but Black-capped Petrel has smaller black cap, usually more white on collar and rump, longer tail, black bar on underwing.
Size
About the size of a Crow, About the size of a Robin
Color
Black, White
Wing Shape
Long, Pointed, Tapered
Tail Shape
Pointed, Rounded, Wedge-shaped

Songs and Calls

Usually silent at sea.
Call Pattern
Flat, Rising
Call Type
Hoot, Raucous, Scream

Habitat

Open ocean. Forages over warm deep water far off southeastern coast of North America, especially over western edge of Gulf Stream. Also over seamounts or submarine ridges where turbulence may bring food nearer surface. Nests around steep forested cliffs in West Indies; may have nested in burrows on more level ground before exotic predators were introduced there.

Behavior

Eggs

One. White. Incubation period unknown; in the closely related Bermuda Petrel, incubation is by both parents, 51-54 days.

Young

No details known. In Bermuda Petrel, both parents feed young, and young bird flies out to sea 90-100 days after hatching.

Feeding Behavior

Often in loose small flocks, associated with other seabirds. Forages by dipping to surface of water, with feet down and pattering on water, or by settling briefly on water with wings upstretched; sometimes feeds while swimming. May do most feeding early morning and late evening, when some prey items are closer to surface.

Diet

Includes squid and fish. Diet not well known. Besides small squid and fish, may scavenge floating carrion or refuse; attracted to slicks of natural oils.

Nesting

Breeding behavior still poorly known. Nesting season begins late fall, lasts to spring. Nests in colonies; known colonies today are on steep cliffs where forest holds enough soil in place for excavating nest burrows. Active around colonies only at night. Birds do much calling as they fly around cliffs in the darkness; courtship may involve flying in pairs. Nest: Site is evidently in burrow in soil. Adults undoubtedly dig their own nest burrow.

Climate Vulnerability

Conservation Status

Formerly an abundant nester on several islands, but numbers dropped sharply in middle of 19th century. Decline often blamed on introduction of mongoose, but that occurred in 1870s, after decline already apparent. Introduced rats more likely responsible, along with humans catching petrels for food. Now known to nest in mountains in Haiti, Dominican Republic, and Cuba, and vulnerable in these few spots.