[order] PROCELLARIIFORMES | [family] Hydrobatidae | [latin] Oceanodroma leucorhoa | [authority] Vieillot, 1818 | [UK] Leachs Storm-Petrel | [FR] Oceanite culblanc | [DE] Wellenlaufer | [ES] Paino Boreal | [NL] Vaal Stormvogeltje
Storm-petrels are rather small and often dark colored tubenoses with a world wide distribution. All have fine black bills with very pronounced tubes. Storm Petrels are separated in two groups: the long legged, Southern Hemisphere birds subfamily Oceanitinae and the shorter legged species of more northern seas the subfamily Hydrobatinae. The first groups shows more morphological differences than the second. The genera are characterised on colour patterns, the condition of the nasal tubes, tail shape, structure of claws and proportions of the leg bones. The genus Oceanodroma consists of medium-sized petrels; plumage dark or greyish, often with pale rumps; tail more or less forked; tarsus short , middle toe with claw and scutellate; claws narrow.
The Leach’s Storm-Petrels found off the coast of Washington are dark, with long, slender wings. They have white rumps, unlike populations farther to the south, which have darker rumps. This storm-petrel appears uniformly dark from below, but from above, some color differentiation is evident. Its tail and flight feathers are black, and its back and head are dark brown. A lighter tan band runs diagonally down the middle of the wing, separating the brown from the black.
Unlike many other tube-nosed seabirds, Leach’s Storm-Petrels do not regularly follow and scavenge from ships. They fly low over the water with irregular wing-beats and forage by taking food from the water while hovering or skimming the water’s surface. They sometimes forage near feeding whales or seals, but seldom sit on the water to feed. They are difficult to observe on their nesting colonies since they enter and leave the colonies only at night.
Listen to the sound of Leachs Storm-Petrel
Copyright remark: Most sounds derived from xeno-canto
Pacific Ocean, Atlantic Ocean : North, Central. Leach’s Storm Petrel has an extensive global range. Breeding colonies are confined to the northern hemisphere, from the South Kuril Islands (Japan) round to Baja California (Mexico) including the Aleutian Islands, Alaska (USA) and Canada in the Pacific, and in the north-east North America, Iceland, northern United Kingdom and Norway in the Atlantic. Northern populations migration south into the tropics in winter, reaching the equator in the Pacific and as far south as south Brazil and South Africa in the Atlantic.
During the nesting season, Leach’s Storm-Petrels inhabit small, offshore, island colonies in the Pacific and Atlantic Oceans. They nest in burrows, so these islands must offer sufficient soil or rock crevices. Outside the nesting season, they disperse over the open ocean, far from land, concentrating around upwellings and areas where cold and warm water meet. These areas are rich in food.
Long-lived birds, sometimes living more than 24 years, Leach’s Storm-Petrels do not breed until they are at least four or five years old. Their nest burrows are situated under grass, rocks, or tree roots. Burrows are typically 1-3 feet long, and can be more than 5 feet long. The male digs the burrow, using his feet and bill. Neighboring burrows may be close together, sometimes sharing a common opening. Natural crevices may also be used. At the end of the burrow is a nest chamber that is lined with twigs, leaves, and grass. Both parents incubate the single egg. Incubation can last from 37-50 days, with an average of 42 days. (Incubation may be interrupted for days at a time, accounting for the large variance.) Both parents feed the young by regurgitating their stomach contents. If the adults do not return regularly with sufficient food, the chick will go into torpor. The ability of the egg to survive with suspended incubation and for the chick to become torpid are important for survival, since the adults spend a lot of time away from the nest looking for food that can be hard to find. After 9-10 weeks, the fledglings leave the island and head to sea on their own.
Small crustaceans make up the majority of the diet, although small fish and squid are also taken. Oil and fat slicks from dead marine mammals are also sources of food for storm-petrels. They have a well-developed olfactory sense and can locate food sources by smell.
Video Leachs Storm-Petrel
copyright: Alain Fosse
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Oceanodroma leucorhoa breeds on remote islands in north-western Europe, which accounts for less than a quarter of its global breeding range. Its European breeding population is large (>120,000 pairs), and was stable between 1970-1990. Although
trends were not available for key populations in Iceland and the United Kingdom during 1990-2000, there was no evidence to suggest that the species declined.
Migratory. North Atlantic breeding birds migrate south to winter in regions of tropical convergences, some stragglers remaining in north. Main arrivals in tropics off west Africa from late November; main concentrations over upwellings (typically not mid-oceanic). Uncertain, but probably rather small, proportion may pass beyond tropics, a few reaching Cape seas. Northward migration both sides of Atlantic, March; most adults presumed to have left tropics by mid-April, as first arrivals Newfoundland in 1st week May and British colonies reoccupied from late April.
Essentially oceanic, but occasionally blown ashore or inland by storms at sea; generally few involved but one major wreck this century: 21 October-8 November 1952, with greatest mortality Britain and Ireland; followed persistent severe westerly gales in Atlantic. c. 2600 in Bridgwater Bay, Somerset, alone, and probably over 7000 died Britain and Ireland, some numbers inland. Many fewer died elsewhere, but 70 Belgium, and one as far inland as Switzerland, while several in south France (Herault) in early November thought driven overland from Bay of Biscay.
Title Where two oceans meet: distribution and offshore interactions of great-winged petrels Pterodroma macroptera and Leach?s storm petrels Oceanodroma leucorhoa off southern Africa
Author(s): Kees C. J. Camphuysen
Abstract: During seabird surveys off southern Africa, great-..[more]..
Source: J Ornithol (2007) 148:333-346
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Title SEABIRD GEOGRAPHIC VARIATION: SIMILARITY AMONG POPULATIONS OF LEACH’S STORM-PETREL
Author(s): DENNIS M. POWER, DAVID G. AINLEY
Abstract: We assessed geographic variation in 13 locality sa..[more]..
Source: The Auk 103: 575-585
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