Murphy's petrel (Pterodroma ultima)
|Size||Length: 38 - 41 cm (2)|
Wingspan: 97 cm (2)
Murphy’s petrel is classified as Near Threatened (NT) on the IUCN Red List (1).
A rare and somewhat enigmatic species of gadfly petrel, Murphy’s petrel (Pterodroma ultima) takes its name from Robert Murphy, the seabird biologist who described the species in 1949 (3).
Murphy’s petrel is dark brownish-grey overall, often appearing darker on the head and greyer on the upperparts. A distinctive dark ‘M’ pattern is faintly visible on the back (4) (5). It is whiter around the throat, with this lighter pattern most conspicuous just below the bill (2) (4) (5), and it has a silvery-white underwing flash across the base of the primaries (4) (5). The tail is short and wedge-shaped. The eyes and bill are blackish, and the legs and feet are pale pink (2) (4) (6). Juveniles of this species are very similar in appearance to the adult (2).
In strong winds, Murphy’s petrel flies in high, steep, wheeling arcs, although in light winds its flight is much less buoyant (5).
During the breeding season, Murphy’s petrel is distributed throughout the Pitcairn Islands and French Polynesia, including the Tuamotu Archipelago, the Austral Islands and the Gambier Islands, in the south-central Pacific Ocean (3) (7) (8) (9) (10). It is thought that this species is generally restricted to islands with a maximum altitude of around 33 metres (7).
Outside of the breeding season, Murphy’s petrel is known to range across the north and central Pacific Ocean, north to the Hawaiian islands, and as far east as the Pacific Coast of North America (4) (7) (9) (10).
Murphy’s petrel is largely a pelagic species, rarely returning to land except for during the breeding season (2). This species nests mainly on rocky cliffs on coral and volcanic islands (2) (7) (11), although it may also use lower-lying atolls and rocky islets (10) (11).
Small cephalopods, such as octopus and squid, make up the bulk of this species’ diet, although Murphy’s petrel also feeds on fish and crustaceans (3) (12). Its short, stout bill, equipped with a powerful hook and sharp cutting edge, is used for gripping and cutting up small squid and fish (13). This species also opportunistically scavenges on larger dead animals that are too big for the petrels to kill or swallow intact, feeding first on the easily-removed eyes (12).
Murphy’s petrel nests on the ground in small colonies, generally in shallow scrapes under trees, shrubs or low vegetation, or in cliff cavities (3) (11). Birds begin the breeding process in late March, and a single, large white egg is laid around late May to mid July (3). Incubation of the egg is shared alternately by both adults (13). The egg hatches in late July to August, and the juvenile Murphy’s petrel remains in the nest for around 100 days (3). The chicks are fed by the adults approximately twice every ten days. Studies suggest that although Murphy’s petrel seems to feed relatively infrequently, the chicks of this species probably receive larger meals than the chicks of other similar petrel species (12).
Outside of the breeding season, Murphy’s petrel migrates to the north and east Pacific, where it spends much of its time at sea. Non-breeding birds may remain in this region throughout the year, being recorded off California between April and July, Alaska in July, and Hawaii in September to November. Evidence suggests that this species probably migrates through the region in an anticlockwise direction (11).
As a ground nesting species, Murphy’s petrel is particularly vulnerable to the presence of introduced predators, such as cats and rats, which prey on eggs, chicks and adults. On Henderson Island in particular, introduction of the Pacific rat (Rattus exulans) has resulted in low breeding success for Murphy’s petrel (3) (7) (11). Additional predation by humans, feral cats and pigs may have decimated populations of this species on Pitcairn Island (11).
Climate change is also a potential threat to Murphy’s petrel due to its restricted distribution on low-lying oceanic islands. In addition, the recent construction of an airstrip in the Tuamotu Archipelago may have affected breeding colonies on some islands (7).
Although Murphy’s petrel only breeds at a handful of locations in the south-central Pacific Ocean, the eradication of rats on Ducie in the Pitcairn Islands has secured what is currently thought to be the largest population of this species (7).
A bid by the RSPB to begin a rat eradication programme on Henderson Island is also in progress, which would further benefit conservation efforts for this and other seabird species, such as the Endangered Henderson Petrel (Pterodroma atrata) (14).
Find out more about conservation in the Pitcairn islands:
UK Overseas Territories Conservation Forum:
Find out more about Pacific seabirds:
Pacific Seabird Group:
Find out more information about Murphy’s petrel and other birds:
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- Cephalopod: from the Greek for ‘head-foot’, a class of molluscs that occur only in marine habitats. All species have grasping tentacles, and either an internal or external shell. Includes nautiloids, cuttlefish, squids, octopuses, and extinct ammonites and belemnites.
- Crustaceans: diverse group of animals with jointed limbs and a hard chitinous exoskeleton characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps and barnacles.
- Feral: previously domesticated animals that have returned to a wild state.
- Incubation: the act of incubating eggs, that is, keeping them warm so that development is possible.
- Pelagic: applied to sea birds that come to land only to breed, and that spend the major part of their lives out at sea.
- Primaries: the main flight feathers projecting along the outer edge of the wing.
IUCN Red List (February, 2011)
- del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
Pitcairn Islands Philatelic Bureau - Murphy’s petrel (February, 2011)
- Dunn, J. and Alderfer, J.K. (2006) National Geographic Field Guide to Birds of North America. National Geographic Books, Washington.
- Howell, S.N.G. and Webb, S. (1995) A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, Oxford.
- Harper, P.C. and Kinsky, F.C. (1974) Southern Albatrosses and Petrels: An Identification Guide. Price Milburn & Co. for Victoria University Press, Wellington.
BirdLife International (February, 2011)
Seabird Osteology (February, 2011)
- Campbell, R.W. (2011) The Birds of British Colombia: Passerines: Wood-warblers through Old World Sparrows. UBC Press, Vancouver.
- MobileReference (2009) The Illustrated Encyclopedia of North American Birds: An Essential Guide to Common Birds Of North America v.10.1. MobileReference, Boston.
- Bartle, J.A., Hu, D., Stahl, J-C., Pyle, P., Simons, T.R. and Woodby, D. (1993) Status and ecology of gadfly petrels in the temperate North Pacific. In: Vermeer, K., Briggs, K.T., Morgan, K.H., Siegal-Causey, D. (Eds.) The Status, Ecology and Conservation of Marine Birds of the North Pacific. Special Publication, Ministry of Supply and Services, Canadian Wildlife Service, Canada.
- Imber, M.J., Jolly, J.N. and Brooke, M. de L. (1995) Food of three sympatric gadfly petrels (Pterodroma spp.) breeding on the Pitcairn Islands. Biological Journal of the Linnean Society, 56: 233-240.
- Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
UK Overseas Territories Conservation Forum (February, 2011)