Little Shearwater (Puffinus assimilis)

Little Shearwater

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Puffinus assimilis | [authority] Gould, 1838 | [UK] Little Shearwater | [FR] Puffin semblable | [DE] Kleiner Sturmtaucher | [ES] Pampero Chico | [NL] Kleine Pijlstormvogel

Subspecies

Monotypic species

Genus

Until recently the shearwaters were devided in two genera Calonectris and Puffinus, but based on dna-analysis Penhallurick and Wink (2004) have proposed a splitting of the shearwaters into three genera: Calonectris for the large shearwaters of the Northern Atlantic, the Mediterranean and the waters around Japan, Ardenna for a group of large Southern Hemisphere breeders and Puffinus for the smaller shearwaters such as the Manx’ group, Audubon’s and Little Shearwaters. This new taxonomy is now widely accepted, but not by all and is stil subject of discussion.

Physical charateristics

The Little Shearwater is the smallest of all Shearwater’s. The upperparts of the species are slate black with a greyish bloom in fresh plumage. In contrast, the underparts are almost entirely white with only the wings having thin black, trailing edges and tips. Individuals have a long, slender bill and light blue legs and feet and black crown.
The species is quiet at sea, however, a wide variety of calls may be heard at breeding colonies. Whilst in courtship, the species vocalises in a throaty, asthmatic sound. Unlike other shearwaters, Little Shearwater seems to be largely confined to the waters close to the breeding islands and visits the nesting sites outside the breeding period.

Listen to the sound of Little Shearwater

[audio:http://www.planetofbirds.com/MASTER/PROCELLARIIFORMES/Procellariidae/sounds/Little Shearwater.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by Niklas Holmstrom


wingspan min.: 58 cm wingspan max.: 67 cm
size min.: 25 cm size max.: 39 cm
incubation min.: 52 days incubation max.: 58 days
fledging min.: 70 days fledging max.: 58 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Atlantic Ocean, Indian Ocean, Pacific Ocean : Southwest Pacific, Southeast Indian Ocean and Australasia, Subantarctic New Zealand, Gough and Tristan da Cunha Is.

Habitat

This seabird lives all year relatively near to its breeding area but is very rarely seen and/or identified since it does not follow ships and, with its wave-top flight, is easily missed.

Reproduction

Little Shearwater is a pelagic bird that nests on the cliffs of small islands and rocks. It builds its nest in rock cavities and under loose stones. Little Shearwaters are monogamous parents that share incubation of the egg for 52 to 58 days.
Both parents feed the chick by incomplete regurgitation for a nestling period of 70 to 75 days The eggs, one per pair of birds, are laid no later than February and the juveniles leave their nests in May/June, when these are then occupied by Bulwer’s Petrels or Cory’s Shearwaters.

Feeding habits

Little Shearwaters primarily eat squid, krill and small fish. Individuals feed by plungediving, surface-seizing and pattering across the surface with wings raised above the back. The species has been observed feeding with dolphins.

Video Little Shearwater

httpv://www.youtube.com/watch?v=cTqoruJXD7U

copyright: P. Fraser


Conservation

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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very 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.
Bulweria bulwerii breeds in the Azores, Madeira and the Canary Islands, which
together account for less than a quarter of its global breeding range. Its European
breeding population is small (as few as 7,000 pairs), and underwent a moderate decline
between 1970-1990. Although the trend in the Canary Islands during 1990-2000
was unknown, the species remained stable in its stronghold in Madeira, and was
stable overall. Nevertheless, its population size renders it susceptible to the risks
affecting small populations.
This pelagic bird inhabits the Atlantic, Pacific and Indian oceans, being much more numerous in the Southern Hemisphere. The European population inhabits the Canary Islands, the Azores and Madeira. It amounts about 2700-3900 breeding pairs. This species is adversely affected by the introduction of rats on its breeding islands, and the population of the Canary Islands has strongly decreased during the last 20 years.
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.
Nevertheless, more than 90% of the European breeding population occurs at 10 sites
Little Shearwater status Least Concern

Migration

Present around colonies east Atlantic all or most of year, partly due to varying nesting seasons. All populations dispersive to some extent after breeding, but no long-distance migration.

Distribution map

Little Shearwater distribution range map

Literature

Title Influence of migratory behaviour on the morphology and breeding biology of Puffinus Shearwaters
Author(s): Bull, L.S.
Abstract: Ecological, life-history, breeding biology and mor..[more]..
Source: Marine Ornithology 34: 25-31.

download full text (pdf)

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