Leach’s storm petrel is a small northern hemisphere seabird that breeds on islands in the North Pacific and North Atlantic Oceans north of 30o N, migrating to tropical and subtropical seas north of the equator. Records of these birds in New Zealand seem a little surprising but they have been found here six times since 1922, including two birds apparently prospecting for nest sites on tiny Rabbit Island, off the north-west end of Pitt Island, Chatham Islands, in 1980, and a pair on an egg on nearby Rangatira Island in 2018.

Identification

Leach’s storm petrel is a small brownish-black seabird with a white band across the rump and a diagonal greyish band across the inner part of the upper wing. The tail is deeply forked and the white rump is divided by a fine dark line visible at close range. The legs are short and black, and the bill is also black. In flight the wings are long and more pointed than in the southern storm petrels, and the tail is longer. The flight pattern is also quite different, agile with sudden changes of direction and speed, with tern-like wing beats and shearwater-like glides on down bowed wings. It may also move slowly into the wind with the feet pattering when feeding.

Voice: soft chuckles and purrs in flight and on the ground. One in a burrow on Rabbit Island gave a loud churring call interspersed with ‘ik’ notes.

Similar species: in size and colour Leach’s storm petrel is most similar to Wilson’s storm petrel but is larger with a more slender build with longer, more pointed wings, a longer forked tail and, usually, a different flight pattern. Other black-and-white storm petrels have white under the wings and on the body, and other dark petrels are larger and lack the white rump.

Distribution and habitat

The form of Leach’s storm petrel that reaches New Zealand breeds on islands in the northern Atlantic and Pacific Oceans, extending down to northern California. They migrate to warmer water usually north of the equator but are regular during the non-breeding season off the Cape of Good Hope and Brazil. Elsewhere they are vagrants, apart from about 25 pairs breeding on islands off the coast of South Africa (breeding suspected since c.1971, confirmed in 1996). 

New Zealand records

Three birds have been washed ashore dead: Muriwai Beach, Auckland (August 1922), Dargaville Beach (August 1978), and Ninety Mile Beach (October 1998). Another was blown inland and found dead at Turangaomoana, near Waharoa on the Hauraki Plains in April 1978. Two live birds apparently prospecting for nest sites were found on Rabbit Island, Chatham Islands in November 1980, and a pair were found on an egg in a burrow near the summit of Rangatira Island, Chatham Islands, in February 2018.

Threats and conservation

Leach’s storm petrel is globally common with a total population estimated at 20,000,000 that appears to be more or less stable.

Behaviour and ecology

Leach’s storm petrels are much more common over deep water than the continental shelf and favour upwellings.

Food

Leach’s storm petrel consume small fish, squid, crustaceans and offal from the sea surface.

Websites

BirdLife factsheet

Wikipedia

References

Fooks, P. 1978. Leach’s fork-tailed storm petrel. Notornis 25: 278.

Harrison, P. 1983. Seabirds: an identification guide. A.H. & A.W. Reed Ltd, Wellington.

Heather, B.D.; Robertson, H.A. 1996. The field guide to the birds of New Zealand. Viking, Auckland.

Imber, M.J.; Lovegrove, T.C. 1982. Leach’s storm petrels (Oceanodroma l. leucorhoa) prospecting for nest sites on the Chatham Islands. Notornis 29: 101-108.

Marchant, S.; Higgins, P.J. (eds) 1990. Handbook of Australian, New Zealand and Antarctic birds. Vol.1, ratites to ducks. Oxford University Press, Melbourne.

Tennyson, A.J.D. 2010. Procellariiformes. Pp. 64-135. In: Checklist Committee (OSNZ) 2010. Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica (4th ed.). Ornithological Society of New Zealand & Te Papa Press, Wellington.

Underhill, L.G.; Crawford, R.J.M.; Camphuysen, C.J. 2002. Leach’s storm petrels Oceanodroma leucorhoa off southern Africa: breeding and migratory status, and measurements and mass of the breeding population. Transactions of the Royal Society of South Africa 57: 43-46.

Whittington, P.A.; Dyer, B.M.; Crawford, R.J.M.; Williams, A.J. 1999. First recorded breeding of Leach’s storm petrel Oceanodroma leucorhoa in the Southern Hemisphere, at Dyer Island, South Africa. Ibis 141: 327-330.

Recommended citation

Southey, I. 2013 [updated 2018]. Leach’s storm petrel. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz