Leach's Storm Petrel

The Leach's storm petrel, or Leach's petrel, is a diminutive seabird belonging to the tubenose order. It is named in honor of the British zoologist William Elford Leach. This species is characterized by its small stature, measuring 18–21 cm in length with a wingspan of 43–48 cm. Its plumage is predominantly dark, with a distinctive white rump, although variations exist, particularly in the dark-rumped individuals found on the west coast of North America.

Identification Tips

In Europe, the Leach's storm petrel can be distinguished from its relatives, the European storm petrel and Wilson's storm petrel, by its larger size, forked tail, contrasting rump pattern, and unique flight behavior. In the Americas, identification is more challenging. On the Atlantic Coast, it can be confused with the band-rumped storm petrel, and on the Pacific Coast, the dark-rumped form may be mistaken for other all-dark storm petrel species. Observers should note the extent of white on the rump, wingbeats, and overall color for accurate identification.

Habitat

Leach's storm petrel breeds on remote and inaccessible islands in the colder northern regions of the Atlantic and Pacific Oceans. It prefers well-concealed nesting sites such as rock crevices, shallow burrows, or even within logs.

Distribution

This species is strictly pelagic outside the breeding season, making it a rare sight from land except during storms or specific migratory conditions. The largest known colony is located on Baccalieu Island off eastern Canada.

Behaviour

Leach's storm petrel exhibits nocturnal behavior at breeding sites to evade predators like gulls and skuas. It avoids landing on clear, moonlit nights. Its flight is described as fluttering, and it patters on the water's surface to forage for planktonic food items.

Breeding

The bird lays a single white egg, often marked with a faint ring of purple spots at the larger end. It breeds in colonies close to the sea and is strictly nocturnal at these sites to avoid predation.

Similar Species

In Europe, similar species include the European storm petrel and Wilson's storm petrel. In the Americas, similar species include the band-rumped storm petrel and other all-dark storm petrel species.

Diet and Feeding

Leach's storm petrel primarily feeds on plankton, such as euphausiids, copepods, and amphipods, as well as myctophids (lantern fish). They can forage up to 1000 km from their breeding colony and store energy-rich lipids in a sac anterior to their stomach for feeding chicks or self-sustenance during incubation.

Conservation status

The Leach's storm petrel is currently classified as Vulnerable on the IUCN Red List of Threatened Species.