Gould's petrel (Pterodroma leucoptera ) is a species of seabird in the family Procellariidae. The common name commemorates the English ornithologist and bird artist John Gould (1804-1881).
Gould's petrel is sometimes known as the white-winged petrel, but as other closely related gadfly petrels have considerably more white on the underwing the former name is preferred. Gould's petrel is the name chosen by W.B. Alexander in his classic work Birds of the Ocean.
Gould described this bird in 1844, naming it Cook's petrel (Procellaria cookii ) after James Cook. In his 1865 Handbook he changed the name to white-winged petrel (Aestrelata leucoptera ).
Today it is known as Gould's petrel (Pterodroma leucoptera ).
A piscivore is a carnivorous animal that eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the die...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
A burrow is a hole or tunnel excavated into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct ...
Soaring birds can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by m...
Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, b...
Monogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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starts withGould's petrel is a small gadfly petrel, white below and dark brown and grey above. The species is classified within the subgenus Cookilaria, all members of which have a dark M pattern across the upper wings. Gould's petrel has long narrow wings, a short rounded tail and the head is noticeably dark, with a white forehead and face. Gould's petrel is 30 cm in length with a wingspan of 70 cm and weighs 180–200 g. Males are slightly larger than females.
Gould's petrels spend most of their life at sea and come ashore only to breed.
Prior to the 1990s it was thought that the Australian subspecies of Gould's petrel bred only on Cabbage Tree Island off Port Stephens in New South Wales. After the discovery of a small number of breeding pairs on neighbouring Boondelbah Island, translocation of 200 chicks in 1999 and 2000 has established a small satellite colony which breeds in artificial nest boxes that were installed prior to the first translocation. In December 2009, just one month after it had been confirmed that rabbits had been eliminated from Cabbage Tree Island, one single Gould's petrel was found incubating an egg on another nearby island, Broughton Island.
Today, the nominate subspecies breeds on at least five islands off New South Wales (Cabbage Tree Island, Boondelbah Island, Broughton Island, Little Broughton Island, and Montague Island). The New Caledonian subspecies breeds on New Caledonia on steep forested valleys on the central mountain chain, from 350–500 metres above sea level between Mountains Dzumac and Poya. There is also a small colony on Raivavae in French Polynesia.
Both subspecies forage in the Tasman Sea during the breeding season and may venture as far west as the Indian Ocean south of south-western Western Australia before laying. After breeding, Gould's petrel migrates to the central (P. l. leucoptera ) and eastern (P. l. caledonica ) Pacific Ocean.
Gould's petrels (of unknown subspecies) were sighted in December 1994 in waters south of Western Australia. It is deduced that these were not breeding birds, because in December breeding birds are incubating (see Life history below), and these waters are too far from the breeding colonies for a foraging trip.
Gadfly petrels have relatively long breeding seasons. They are generally monogamous and form long-term pair bonds.
While most petrels nest in burrows, as do the Gould's petrels on New Caledonia, the Australian subspecies of Gould's petrel does not. On Cabbage Tree Island, they nest in amongst rocks and boulders, under fallen palm fronds, in hollow trunks of fallen palms and between buttresses of fig trees.
On Cabbage Tree Island, birds arrive in mid-October to secure their nest site and reunite with their mate. In November they return to sea for 2–3 weeks (the 'pre-laying exodus'). The single egg (which is not replaced if lost) is laid between 18 November and 10 December. Incubation is undertaken by both parents and takes 6–7 weeks. Males undertake the first shift which can be as long as 17 days. Females then take over for a shorter shift. Finally, males take the final shift until the egg hatches, usually in January. The chick reaches a maximum body mass that is often more than 130% of adult body mass. The young fledge in April to May at 80–100 days of age and a body mass of 160–180 g.
The age at which Gould's petrels commence breeding is unknown. The youngest bird of the Australian subspecies known to breed was 12 years of age. Young birds are thought to spend the first 5–6 years at sea before starting to breed. However, during this time they do return to their natal breeding colony to establish pair-bonds and to learn courtship and breeding skills.
The longevity of Gould's petrel is unknown. The oldest known member of the Australian subspecies was at least 23 years old.
Little is known about the diet or feeding behaviour of Gould's petrels. We do know that they eat small cephalopods and fish, and that variation in foraging success is substantial.
Procellariiforms go without food during often lengthy incubation shifts.
The main threats to the nominate subspecies are the introduction of feral predators (cats (Felis catus ), black rats (Rattus rattus ), foxes (Vulpes vulpes ) or dogs (Canus familiaris )) or wild fire, particularly in December when birds are incubating. Because of their chosen precarious nesting habits, accidental egg breakage is not unusual.
The major threat to the New Caledonian subspecies is introduced predators within the breeding colonies. Introduced pigs (Sus scrofa ) dig up burrows and black rats prey on birds and eggs. In addition, adults are killed at night when they fly into lights on Nouméa.
Threats to Gould's petrels at sea are unknown; though they are not known to be affected directly by long-line fishing operations.
In the early 1990s the breeding population of the Australian subspecies was fewer than 250 pairs. Breeding success was less than 20% and fewer than 50 young fledged each year. Each year more adults died than chicks fledged successfully. In 1992 scientists estimated that the population had declined by 26% over the previous 22 years.
Research revealed that the major problems threatening processes were (a) sticky fruit of the birdlime tree (Pisonia umbellifera ) which immobilised birds; (b) predation by pied currawongs (Strepera graculina ) and (c) habitat degradation caused by grazing of European rabbits (Oryctolagus cuniculus ). Rabbits had eaten the undergrowth allowing sticky birdlime fruit to fall to the ground, so birds, both adults and chicks, were exposed to fruit which would otherwise have been entangled in shrubbery.
Active conservation management for the Australian subspecies of Gould's petrel has been so successful that the conservation status of the subspecies has been down-graded from endangered to vulnerable. In 2010, the total population of the Australian subspecies was estimated to be 2,500 individuals and increasing.
At the same time, the population of the New Caledonian subspecies was estimated at 10,000 individuals and decreasing. However, this number is no more than an estimate and scientists do not have high confidence that it is correct.
The New Caledonian subspecies is also classified as vulnerable because of its restricted geographic breeding range.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...