Black-vented Shearwater

The Black-vented Shearwater, known scientifically as Puffinus opisthomelas, is a medium-sized seabird with a body length ranging from 30 to 38 centimeters and a wingspan stretching between 76 and 89 centimeters. Its plumage and taxonomic relationships are subjects of interest, as it was once considered a subspecies of the Manx shearwater.

Identification Tips

This species can be identified by its distinctive black vent, which contrasts with its otherwise predominantly brown and white plumage. Observers should note its sleek, aerodynamic body shape typical of shearwaters, which aids in its effortless flight over the ocean.

Habitat

The Black-vented Shearwater is a pelagic bird, spending much of its life on the open ocean. It is known to venture closer to land than many of its relatives, providing opportunities for shore-based observations.

Distribution

The species is found in the Pacific Ocean and the Gulf of California. During the colder months, it is fairly common off the central and southern coasts of the United States, particularly California.

Behaviour

This bird exhibits colonial nesting habits, preferring to lay its eggs in burrows and caves on offshore islands. It is a resilient species, having overcome past threats from feral predators on its breeding grounds.

Breeding

The Black-vented Shearwater predominantly nests on islands off north and western Baja California, with a significant population on Isla Natividad. The species' breeding sites are critical for its continued survival.

Diet and Feeding

The diet of the Black-vented Shearwater mainly consists of small fish, which it captures with skill in the marine environment.

Conservation status

The IUCN has classified the Black-vented Shearwater as Near Threatened. While past threats from feral cats have been largely mitigated, the species now faces uncertain impacts from the expanding fishing industry, including potential losses from commercial gill netting.