Murphy’s Petrel
Pterodroma ultima
Procellariiformes Order – Procellariidae Family
INTRODUCTION:
The Murphy's Petrel was only described as a species in 1949. The common name pays tribute to Robert Cushman Murphy who described the bird for the first time.
It is found in SC Pacific Ocean and breeds on rocky islets and cliffs on Austral Islands, Tuamotu, Pitcairn Islands and Easter Island. But the species has also been recorded as far off as the Hawaiian Islands, the Pacific coast of the United States and also in the Southern Gulf of Alaska.
This bird is marine and pelagic, having one of the greatest foraging ranges among other breeding seabirds.
The Murphy's Petrel usually feeds on fish, squid, cephalopods and small crustaceans, and generally takes small marine prey.
It breeds on small rocky islands in South Pacific. The nest is a shallow scrape built at base of rock or small tree, sometimes in rocky cavities. Both adults share the nesting duties.
The Murphy's Petrel has very large range. The species is affected by predation by rats on some islands during the nesting period, but this problem does not impact the global population size, and currently, the species is not globally threatened.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 35-41 cm
Wingspan: 89-97 cm
Weight: 335-435 g
The Murphy's Petrel is a medium-sized, fairly stocky gadfly petrel. The term “gadfly” used for these petrels alludes to the impulse that drives them to fly swiftly in wide arcs above the sea, as if pursued by a gadfly!
It is mainly dark grey and brownish-grey, with paler area around the bill base.
On the upperparts, mantle, back and scapulars are paler and greyer, whereas upperwing and tail are brownish-grey, with a brown “M” across both wings and lower back. Depending on feather-wear, both secondaries and back may show a “frosted” appearance, with some pale grey areas.
The underparts are uniformly grey, although in some lighting, the belly may appear paler while the breast appears darker.
On the dark underwing, we can see a large, whitish or silvery patch at base of primaries. This patch may sometimes extend into the outer primary coverts and secondaries.
The head appears sooty-brown overall, and shows an indistinct whitish area around the base of the bill. At close range, the nasal tubular structure is conspicuous on the top of the bill.
The bill is black.
The eyes are dark brown.
Legs and inner base of the feet are pink-flesh to pale fleshy-grey, while the rest of the feet is greyish-black.
Male and female are similar in appearance, but the male is larger.
The juvenile resembles adult.
The fledgling has dark, dense down overall, with a darker area around the eye.
RANGE:
The Murphy's Petrel occurs in the South Pacific and breeds on Austral Islands, Tuamotu, Pitcairn Islands and Easter Island.
The non-breeding birds can be found as far north as the Hawaiian Islands, and as far east as off the west coast of the United States.
HABITAT:
The Murphy's Petrel spends most of its time at sea, and comes ashore only for nesting.
It breeds on small rocky islands, islets and cliffs, often remote and tropical oceanic islands.
The nest is a shallow scrape on the ground, protected by small or fallen tree, or placed under tussocks of grass. It is rarely built in direct sunlight. It also use rocky cavities in cliffs.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The vocalizations of the Murphy's Petrel are not well known. But some sounds have been recorded during observations.
Two calls are described, given by a pair during the pre-breeding period.
The first call is described as a soft, owl-like hoot, usually given from the ground and when both mates are allopreening. It is rendered as “hoo-hoo-hoo-hoooooooo” with a final syllable lasting three seconds. While producing this call, the petrel does not open the bill, but the throat can be seen pulsating in time with the call.
The second call is given with an open bill. It is described as a tri- or quadri-syllabic yelping cry, with the stress on the first syllable. It is given both in flight and from the ground where it could be associated with intrusions into the nesting territory. It is sometimes given by both mates at the nest-site. A shrill “ki-ki-ki” has also been reported.
The birds are usually silent at sea, but they become noisy at night at the colonies.
BEHAVIOUR IN THE WILD:
The Murphy's Petrel feeds mainly on fish, squid, small crustaceans and various small marine creatures. It typically feeds by flying over the water surface, dipping down or skimming prey from the surface. It may also catch a prey just below the surface, while maintaining the flight.
Generally, the gadfly-petrels engage in elaborate aerial chases with high-speed swoops and towering, accompanied by loud calls at the beginning of the breeding season.
Both adults build a shallow scrape on the ground, protected by small tree or tussock grass. But they also nest in rocky cavities on cliffs. Both parents share the nesting duties. They are colonial nesters.
Following the breeding season, the Murphy's Petrel probably disperses within the tropical Pacific after breeding. The breeding areas are completely abandoned outside of breeding season. The non-breeding birds can be found as far north as the Hawaiian Islands, and as far east as off the west coast of the United States.
The Murphy's Petrel is a usual visitor from mid-April to early June, well offshore near the interface between the warm waters of the North Pacific Gyre and the cold waters of the California Current.
They are frequently found in deep pelagic waters, as far north as 54°N, with records in the Gulf of Alaska.
The gadfly-petrels fly fast and sometimes low over the water or by wheeling up into the sky or “towering”. They fly with rapid wingbeats interspersed with gliding. They feed on the wing and alight rarely on the water.
REPRODUCTION OF THIS SPECIES:
The laying occurs between May and July in the breeding islands of Austral pacific, including Pitcairn, Tuamotu, Austral and Cook island groups. Hatching occurs between mid-July and end of August.
The breeding season varies depending on the range.
The Murphy's Petrel is a colonial breeder and visits the colonies at night. The colonies are established on remote rocky islands, islets, rocky cliffs on offshore stacks, and sometimes on the ground, but rarely in direct sunlight. The nest, a shallow scrape, is protected by overhanging rock, small tree or tussocks of grass. Several islands have a maximum elevation of 33 m, making them vulnerable to sea-level rise.
The female lays a single white egg. Both adults share the long incubation lasting up to 50 days, in three fairly long turns of about 19 days. At hatching, the chick has sooty-brown to sooty-grey down, and a darker area on the forehead and around the eyes. It is fed by both parents about every fifth day. It fledges about 100 days after hatching.
Predation by rats on some islands is an important threat during the breeding period.
The Murphy's Petrels are known for their unusually long trips during the incubation. This is a distinctive aspect of the breeding behaviour of this species. The agile and sustained flight of this petrel allows the bird to fly over long distance while searching for food.
PROTECTION / THREATS / STATUS:
The Murphy's Petrel has very large range, and currently, the population size is not suspected to be decreasing.
However, the species is affected by predation by the Black rat and the Polynesian rat on several breeding islands, with an important negative impact on fledging success depending on the breeding range.
The species is also vulnerable to sea-level rise on some low islands.
The population is roughly estimated at 800,000/1,000,000 individuals. It is slowly declining but it is not globally threatened at the moment.
The Murphy's Petrel is currently evaluated as Least Concern.
Fr: Pétrel de Murphy
Ang: Murphy's Petrel
All: Murphysturmvogel
Esp: Petrel de Murphy - Fardela de Murphy
Ita: Petrello di Murphy
Nd: Murphy's Stormvogel
Sd: murphypetrell
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
OISEAUX DE MER – Guide d’identification de Peter Harrison – Editions Broquet (Canada) – ISBN-10 : 2890004090 – ISBN-13 : 978-2890004092
A Complete Guide to Antarctic Wildlife by Hadoram Shirihai and Illustrated by Brett Jarrett - Edited by Guy M. Kirwan - ALUL.A Press Oy, Finland - ISBN 9519894705
The calls of Murphy's Petrel (Pterodroma ultima)
MURPHY'S PETREL Pterodroma ultima - non-breeding visitor, occasional at sea
South Dakota Birds and Birding – (Terry L. Sohl)
Wikipedia, the free encyclopaedia