The black-vented shearwater is a species of seabird endemic to islands off of the Pacific coast of Mexico and the Gulf of California. It is a smaller shearwater, with a length of 30–38 cm, 76–89 cm wingspan and a mass of around 400 g. This species is pelagic and feeds mainly on small fish. It is nocturnal, and is most active in low light settings.
Region
Eastern Pacific (Baja California and the California Current)
Typical Environment
Breeds on offshore islands along the Pacific side of the Baja California Peninsula and the Gulf of California. Outside the breeding season it disperses northward along the California Current, commonly reaching the U.S. West Coast and occasionally farther to the Pacific Northwest. At sea it is pelagic over continental shelf edges and upwelling zones, where small schooling fish are abundant. On land it nests in burrows or crevices in sandy or friable soils with low scrub. It comes ashore mainly at night during the breeding season.
Altitude Range
Sea level to 300 m
Climate Zone
Subtropical
Ease of Keeping
Beginner friendly: 1/5
Black-vented shearwaters breed only on a handful of islands off Baja California, Mexico, and visit colonies almost exclusively at night to avoid predators. At sea they often gather in large flocks along productive upwelling zones and may follow fishing vessels, which makes them vulnerable to bycatch. Predator control and habitat protection on key islands such as Isla Natividad have benefited the species. They are agile dynamic soarers, using winds over the ocean to travel long distances efficiently.
A black-vented shearwater flying over the water.
Temperament
social and active
Flight Pattern
short rapid wingbeats interspersed with long glides; dynamic soaring over swells
Social Behavior
Highly colonial, nesting in burrows or crevices on islands. Visits colonies at night and often forms long-term pair bonds, laying a single egg per season. Both parents share incubation and chick rearing. Away from colonies it gathers in flocks over productive feeding areas.
Migratory Pattern
Partial migrant
Song Description
Generally quiet at sea, but at night around colonies it gives wailing, cackling calls and moans. Vocalizations are used for mate recognition and territorial interactions within the nesting colony.
Plumage
Dark brown to sooty upperparts with clean white underparts; under-tail coverts and vent are dusky to blackish, giving the species its name. Underwings are mostly white with dusky edges and carpal area. Texture is sleek and tight-feathered for efficient flight over water.
Diet
Feeds mainly on small schooling fish such as anchovies and sardines, as well as squid and small crustaceans. Takes prey near the surface by surface-seizing and shallow pursuit dives, sometimes pattering along the surface. Often associates with predatory fish, marine mammals, or flocks of seabirds to exploit concentrated prey. Will occasionally follow fishing boats to scavenge discards, which can increase bycatch risk.
Preferred Environment
Forages over coastal and offshore waters, especially along upwelling fronts and over shelf breaks. Concentrates where cold, nutrient-rich waters bring prey to the surface. Typically feeds in areas with moderate to strong winds that support dynamic soaring.
