Black-vented Shearwater (Puffinus opisthomelas)

Black-vented Shearwater

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Puffinus opisthomelas | [authority] Coues, 1864 | [UK] Black-vented Shearwater | [FR] Puffin culnoir | [DE] Schwarzsteiss-Sturmtaucher | [ES] Pardela Culinegra | [NL] Zwartbuikpijlstormvogel

Subspecies

Genus Species subspecies Region Range
Puffinus opisthomelas PO e

Genus

Until recently the shearwaters were devided in two genera Calonectris and Puffinus, but based on dna-analysis Penhallurick and Wink (2004) have proposed a splitting of the shearwaters into three genera: Calonectris for the large shearwaters of the Northern Atlantic, the Mediterranean and the waters around Japan, Ardenna for a group of large Southern Hemisphere breeders and Puffinus for the smaller shearwaters such as the Manx’ group, Audubon’s and Little Shearwaters. This new taxonomy is now widely accepted, but not by all and is stil subject of discussion.

Physical charateristics

A small shearwater, black above and white below; dark cap extends below the eye. The contrasting black and white pattern and gliding, bounding flight are distinctive.

Listen to the sound of Black-vented Shearwater

[audio:http://www.planetofbirds.com/MASTER/PROCELLARIIFORMES/Procellariidae/sounds/Black-vented Shearwater.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 80 cm wingspan max.: 85 cm
size min.: 34 cm size max.: 36 cm
incubation min.: 48 days incubation max.: 50 days
fledging min.: 68 days fledging max.: 70 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Pacific Ocean : East. Puffinus opisthomelas breeds on six islands or small islets (including Guadalupe, San Benito and Natividad), off the Pacific coast of Mexico.

Habitat

Open ocean near coast. Found closer to shore than most she
arwaters, over continental shelf within a few miles of the coast. Favors warm waters at all seasons: fewer move north along California coast in years when sea surface temperature is lower. Nests on islands with enough soil for burrowing or with natural cr
evices in rock.

Reproduction

Breeding behavior not well known. Nests in colonies on islands. Active around colonies only at night. Both members of pair may rest in nest burrow during daytime before egg-laying.
Nest: Site is in burrow in ground, sometimes in natural crevice in rock. Burrow may be more than 10′ long, often with turns to the
side rather than straight; probably both sexes help dig burrow, as in related species. Nest chamber at end of burrow may have a few bits of plant material or may be unlined.
Clutch 1. Dull white. Incubation probably by both sexes, as in other shearwaters; incubation period not well known.
Young: Both parents probably feed young, by regurgitation. Development of young and age at first flight not well known, but young probably remains in nest at least 2 months.

Feeding habits

Probably mostly fish. Diet not well known. Off southern California may eat mostly small fish, including herring and sardines. May also eat small squid, crustaceans.
Behavior: Forages by seizing items at or just below surface
while swimming, by plunging into water from low flight, or by making shallow dives from surface. Apparently does not dive as often nor swim as well underwater as the similar Manx Shearwater.

Video Black-vented Shearwater

httpv://www.youtube.com/watch?v=GGWvMPmPxmE

copyright: Peter Fraser


Conservation

This species declined in the past owing to road building schemes and principally predation by introduced cats. However, these threats have ceased and the population may now begin to increase. Given the species’s longevity it is retained as Near Threatened on the basis of the past declines.
Breeds on sea islands off Pacific Coast
of Baja California. Migration:
Moves north from Baja into California’s coastal waters in fall. Numbers and timing variable: when sea temperature is high, may arrive early and in large numbers. Some also may move well to south of breeding range, but southward migration poorly known.
Black-vented Shearwater status Near Threatened

Migration

Disperses mostly N up W coast of N America to C California and rarely as far as British Columbia; some birds move S, with record of 288 birds just N of Galapagos Is.

Distribution map

Black-vented Shearwater distribution range map

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