Providence petrel  (Pterodroma solandri)

The providence petrel is a robust seabird confined to two small islands off the east coast of Australia (2) (3). Its plumage is almost uniformly dark grey-brown except for the face and chin, which are mottled white (2), and cream triangular patches visible in flight under the wing (3). It has a stout black bill below dark brown eyes. Males tend to be larger than females and have a more prominent ridge (culmen) running along the upper part of the bill (2). These petrels are silent at sea but over breeding colonies produce a boisterous screech which, remarkably, when imitated by humans can lure the birds to the ground (4).

Breeding populations of the providence petrel are only found on Lord Howe Island, and Philip Island of the Norfolk Island group off the east coast of Australia (2). Non-breeding birds, however, are found all across the western Tasman Sea and the entire north pacific, even recorded as far as Japan (2) (5).

Nests are made on forested slopes and mountain summits from sea level up to 900 metres, with adult birds foraging widely at sea, preferring warm waters or the convergence zones between warm and cold currents (2) (6).

Earth burrows or rock crevices underneath the forest canopy are the favoured nesting sites of the providence petrel (2). Breeding takes place over winter, at the same time each year, with the female laying just a single egg (7). Following an incubation period of approximately 55 days, shared attentively by both parents, chicks begin to hatch in mid-July. Once hatched, the parent birds spend most of their time foraging away from the nest, returning only for short periods at night to feed the chick (3). By November most of the chicks will have fledged (8).

With the ability to dive to depths of up to five metres, the providence petrel feeds primarily on fish and squid but will also take crustaceans and, on occasion, scavenge for offal cast from fishing boats (2).

In 1788, when the first Europeans arrived on Norfolk Island to establish a new penal colony for transported convicts, the population of providence petrel was probably in excess of one million pairs. However, uncontrolled hunting by human settlers and predation by introduced animals swiftly decimated the petrel population. By 1825, the seabird had been extirpated from the entire Norfolk Island group, and was not seen for another 150 years, when in 1985 a small population of 20 birds was discovered breeding on Philip Island (2) (9). Despite similar adversity, the breeding population on Lord Howe Island was able to withstand the potentially devastating introduction of a range of animals including pigs, cats, goats, rats and owls. Presently, the population on Lord Howe Island is stable with estimates in 2002 of over 32,000 breeding pairs, but with only a small number recorded on Philip Island, the species remains vulnerable to both catastrophic events and human impacts (2). Fortunately, the current human threat to providence petrels on Lord Howe Island is considered negligible compared with mortality caused by natural flooding of burrows and minor predation by the endemic Lord Howe woodhen (2) (8) (10).

In acknowledgement of its unique biodiversity and natural beauty, Lord Howe Island was declared a World Heritage Site in 1982, and consequently is highly protected and the focus of substantial conservation effort (2) (11). This includes a programme for controlling the introduced black rat, but its effectiveness and relevance for providence petrels has not been assessed (2). Strict quarantine initiatives are also in place on both Lord Howe Island and Philip Island to minimise the risk of introducing invasive pests that could threaten native wildlife (6) (10). In the long-term, and particularly given the threat climate change holds for a species with such a limited range, there is considerable value in assisting in the expansion of a significant breeding population on the Norfolk Island group. Existing proposals include the eradication of mammalian predators from all, or part, of Norfolk Island, and translocation of providence petrel chicks to protected areas (2) (6).

For further information on Lord Howe Island see:

• UNESCO World Heritage – Lord Howe Island:
  http://whc.unesco.org/en/list/186

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk