LEACH’S STORM PETREL

LEACH’S STORM PETREL(Oceanodroma leucorhoa)

The Leach’s Storm Petrel is a pelagic (lives on the open ocean) seabird that only comes to land when breeding, or when pushed inland following storms (hence the name). It is about 20 cm (8 in.) long, with long narrow wings. The plumage is black for the most part, including the bill and feet. They have a white rump and a pale brown bar on the upper wing (see photo below).

Petrels are part of an order of birds that includes seabirds with a ‘tubenose’ bill. This highly specialized bill is made of plates and the nostrils are inside one of them in the shape of a ‘tube’. These birds drink seawater, and they have glands in their bill to extract the salt from the water. Their nostrils also have a self-defensive feature – when threatened they can spit out a foul-smelling oil from that organ. Petrels also have a high sense of olfaction and their bill is equipped to detect food sources near the water surface.

The English name ‘Leach’s’ was given to this storm petrel in memory of William E. Leach, an English marine biologist.. And the name ‘Petrel’ comes from St. Peter walking on the water, because this bird seems to ‘walk’ on the water when feeding.

As for the Latin genus name ‘Oceanodroma’, it means roughly ‘running over the ocean’, an allusion to the bird’s seemingly walking on the water. The species name ‘leucorhoa’ means ‘white’ for its white coverts (the feathers above the tail).

This species of petrel feeds in ocean areas where cold and warm currents meet and bring swarms of small crustaceans near the surface. They usually don’t dive. They will follow whales and dolphins for sources of food, but not fishing boats.

Leach’s storm petrels build their nests in burrows, sometimes including several branches with nests in the end chambers. Those chambers are then lined with plant material. As with other seabirds, they only visit their nests at night, and walk clumsily on land.

The Leach’s storm petrel does not breed on PEI. It breeds on remote islands near the coasts of North America and Asia. It winters in the tropical seas. It is absent from PEI in spring and winter, and uncommon in summer and fall (sightings are likely following storms).

Conservation: The Leach’s storm petrel is listed as ‘vulnerable’ by the IUCN, due to steady declines in its global population. However trends are difficult to assess due to the nocturnal habits of this species when breeding, remoteness of breeding sites, and pelagic behavior. One major threat comes from introduced mammals such as rats and mice on breeding sites. Another one is from predatory birds such as gulls, which hunt them at night on their breeding sites, while another one is collision and stranding due to their attraction to artificial light. There are measures taken in some places to eliminate rodents from the bird’s breeding areas, and also to protect the birds from colliding with sources of artificial light.

Leach's Storm Petrel - Apr. 4, 2006 - C. Schlawe, USFWS
Leach’s Storm Petrel – Apr. 4, 2006 – C. Schlawe, USFWS
Leach's Storm Petrel - Fippennies Ledge off Cape Cod - Aug. 18, 2010 - © Eric Masterson
Leach’s Storm Petrel – Fippennies Ledge off Cape Cod – Aug. 18, 2010 – Eric Masterson

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