Rationale (Changed due to Measured change in population size)

The regional population of Grey Petrel Procellaria cinerea breeds at two locations in the region namely Prince Edward Island and Marion Island. The species is suspected to have met the criterion for regionally Vulnerable after undergoing declines of greater than 30% over a three generation period.

Distribution

The Grey Petrel has a circumpolar distribution in Subantarctic and subtropical waters, mostly between 37°S and 49°S but extending further north in the Humboldt Current to about 18°S off the east coast of South America (Marchant and Higgins 1990). It breeds on a several South African, French, New Zealand and Australian Subantarctic islands, as well as on Amsterdam Island, and in the Gough and Tristan de Cunha group (Brooke 2004). The species also breeds on both Prince Edward and Marion islands (the reason for its inclusion here). It is a rare non-breeding vagrant to continental South African waters, generally remaining in the Southern Ocean for the majority of the year and seldom venturing north of the Subtropical Convergence (Ryan and Bester 2008).

Habitat View more ecological information

Population

Global population data are scarce and accurate census data for most breeding sites are currently lacking (Garnett et al. 2011). The core of the global population occurs on the Antipodes Islands which support 53 000 pairs (Bell 2002), followed by 10 000 pairs on Gough Island (Brooke 2004). Crozet, Kerguelen, Amsterdam, Campbell and Tristan islands hold much smaller populations. The global population is estimated at c. 400 000 individuals (Garnett et al. 2011). Burrow-nesting species are challenging to census accurately, so there is very little information on population trends. Ryan and Bester (2008) provide estimates of 2 000 mature individuals on Marion Island and 10 000 mature individuals breeding on Prince Edward Island, giving a regional population estimate of 12 000 mature individuals. Confidence in this estimate is low.

Population trend

Confidence in the global population trend is low (BirdLife International 2014bq) but moderately rapid declines are suspected. The rate of decline of the regional population is suspected to be greater than 30% over three generations (75 years) but further data are urgently required in order to more accurately assess its population numbers and trends (Garnett et al. 2011). Confidence in this trend estimate is low.

Threats

The primary threat to the global population is incidental mortality caused by commercial longline fisheries (Huyser 2000c). The species is the most commonly caught seabird in New Zealand fisheries and Barbraud et al. (2009) reported declines due to fishery bycatch at the Kerguelen Islands. Regionally, relatively few were killed on toothfish longlines around the Prince Edward Islands (Nel et al. 2002c). The species is susceptible to introduced mammalian predators with populations on Gough Island being thought to have been subjected to considerable predation from introduced mice (Wanless et al. 2007) and the extirpation of the species on Macquarie Island being attributed to cats and rats. There is concern about the possible impact of mice at Marion Island. Prior to eradication in the early 1990s, feral cats on Marion Island predated upon this species (van Aarde 1980). There are no accurate data to monitor the recovery of burrowing petrel populations at Marion Island (Ryan and Bester 2008) but it is thought that the Grey Petrel, a winter breeder, came under extreme pressure from predation by cats.

Conservation

Underway

The Grey Petrel is protected internationally under the Agreement on the Conservation of Albatrosses and Petrels - Annex 1. The species is currently listed as globally Near Threatened, and is included in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals. The Prince Edward Islands are listed as a Ramsar Wetland of International Importance, and as a Special Nature Reserve under the Environment Conservation Act (No 73 of 1989) and the Prince Edward Islands Management Plan 1996. The Prince Edward Islands Marine Protected Area was proclaimed in 2013. A feasibility study for eradication plans to rid Marion Island of mice is currently underway.

Proposed

Public awareness regarding the conservation needs of large petrels should be increased. Mitigation strategies to reduce accidental bycatch for fisheries must be maintained.

Research

* Despite the difficulty thereof, it is important to determine how food availability for Macaroni Penguins fluctuates at both summer and winter-feeding grounds, and to what extent the penguins compete with other predators for prey.

* Further information is required on the foraging distributions, especially during breeding.

* Research into adult and immature survival and recruitment ages of Macaroni Penguins at Marion Island would be beneficial.

* Proposed implantation of transponder tags may assist in determining both population and demographic parameters.

* Further counts of Macaroni Penguins are required for Prince Edward Island.