Streaked Shearwater

The Streaked Shearwater, known scientifically as Calonectris leucomelas, is a medium-sized seabird with an impressive wingspan averaging 122 cm (48 in) and a body length of about 48 cm (19 in). This species is characterized by its sleek, streamlined body adapted for life at sea.

Identification Tips

Adult Streaked Shearwaters are distinguished by their long, slender wings and a tail that is typically wedge-shaped. Their plumage is predominantly brown with lighter, streaked underparts, which gives them their common name. The bill is sturdy and hooked, an adaptation for their piscivorous diet.

Habitat

These birds are pelagic, spending most of their life on the open ocean. They are also known to frequent inshore waters. During the breeding season, they show a preference for forested hills where they can nest in burrows.

Distribution

The Streaked Shearwater is found across the Pacific Ocean. They breed primarily on offshore islands of Japan and the Korean Peninsula. Post-breeding migration takes them south to the seas off northern New Guinea, the Arafura Sea, and the South China Sea. Sightings have also been reported off the west coast of the United States, the southern coast of India, and New Zealand. Remarkably, there has even been a record of a specimen collected in Wyoming.

Behaviour

These birds are known to follow fishing boats, particularly attracted to anchovy crawls off Japan. Unfortunately, they sometimes become by-catch in nets or drown when ingesting bait on long-line fishing lines.

Song & Calls

The vocalizations of the Streaked Shearwater are less commonly heard by casual observers due to their pelagic nature, but they do produce calls, particularly during the breeding season when they are more social and active on their nesting grounds.

Breeding

Streaked Shearwaters are burrow-nesters, often found in forested hills on islands. They lay a single egg and exhibit strong site fidelity, returning to the same burrow year after year.

Similar Species

The Streaked Shearwater may be confused with other shearwater species; however, its streaked underparts and specific flight pattern are good distinguishing features.

Diet and Feeding

The diet of the Streaked Shearwater consists mainly of fish and squid. They are adept at exploiting food sources made available by human fishing activities, although this sometimes leads to their accidental capture.

Conservation status

The IUCN Red List currently classifies the Streaked Shearwater as Near Threatened. Threats include entanglement in fishing nets, predation by introduced species such as cats and rats on breeding islands, and direct harvesting by some human cultures. Conservation efforts are needed to address these threats and ensure the species' long-term survival.