Subspecific taxonomy complex and
confused. Some four subspecies recognized.
O. l. leucorhoa - Northern Japan, Kurile Islands, Commander Islands, eastern Aleutians, North Atlantic from Maine to Scandinavia.
O. l. chapmani - San Benito Island, Baja California.
O. l. socorrensis (Socorro Storm-petrel) - Guadalupe Island off Baja, California.
O. l. cheimonestes
Also known as Fork-tailed Storm-petrel(!),
Leach's Fork-tailed Storm-petrel or Leach's Petrel.
A medium sized storm-petrel of the
north Atlantic and north Pacific. Flies with a distinctive bounding flight
reminiscent of Nighthawks or Nightjars. Deep wing beats interspersed with
short glides on bowed wings. Rapid changes of direction and speed. Sometimes
patters. Not attracted to ships.
Where and When
Total world population in excess
of 10 million individuals. The vast majority of the Atlantic breeding population
breeds in eastern North America (750,000+ pairs) with smaller numbers on
Iceland, The Faeroes, Ireland, Scotland and Norway. Disperse to tropical
and subtropical waters as far south as South Africa. A few even getting
into the Indian Ocean. In the Pacific, breeds in northern Japan (2 million
on Hokkaido), Kurile Islands (350,000 birds) Sakhalin, Commanders, Aleutions
(more than 1 million), Gulf of Alaska (more than 1.2 million), British
Columbia (more than 1.1 million) and south to islands off western Mexico
(Los Coronados, San Benito, Guadelupe and Rocas Alijos). Click
here to view a range map for the Caribbean and central America. Has
reached Australia and New Zealand.
Photographs on the web
In hand, showing details of upperwing, rump patch and tail. Taken in Norway. Photo by Frode Falkenberg
Uppersurface in flight. Photo by Monte Taylor, taken off California.
in flight showing forked tail nicely. Photo by Monte Taylor, taken
Ainley, DG. (1980) Geographic variation in Leach's Storm-Petrel. Auk 97: 837-853.
Ainley, DG. (1983) Further notes on variation in Leach's Storm-Petrel. Auk 100: 230-233.
Bourne, WRP and Jehl, JR (1982) Variation and nomenclature of Leach's Storm-Petrels. Auk 99: 793-797.
Power, DM., and Ainley, DG. (1986) Seabird geographic variation: similarity among populations of Leach's Petrels. Auk 103: 575-585.