Galapagos petrel (Pterodroma phaeopygia)

Also known as:	Dark-rumped petrel
Synonyms:	Pterodroma phaeopygia phaeopygia
Spanish:	Petrel de Galápagos

Kingdom	Animalia
Phylum	Chordata
Class	Aves
Order	Procellariiformes
Family	Procellariidae
Genus	Pterodroma (1)
Size	Length: 43 cm (2) Wingspan: 91 cm (3)

The Galapagos petrel is classified as Critically Endangered (CR) on the IUCN Red List (1) and is listed on Appendix I of the Convention on Migratory Species (CMS or Bonn Convention) (4). It is also listed as Endangered by the U.S. Fish and Wildlife Service (5).

A medium-sized seabird with long wings, the Galapagos petrel is greyish-black across the upperparts, and white on the forehead and underside. The underwings are edged with black and the legs are pink. The feet are also pink, and have black webbing. The black bill is short and hooked, and like all species of petrel, has tubular nostrils that are united at the top. The tail is wedge-shaped and white in colour (3).

The Galapagos petrel is endemic to the Galapagos Islands, this petrel forages to the east and north of the Galapagos archipelago, around western Central America and northern South America (2).

Inhabits rocky areas, making nests in burrows or natural cavities on slopes, in craters, sinkholes, lava tunnels, and gullies (2).

In preparation for long periods of incubation, the female Galapagos petrel leaves the colony to feed for several weeks before returning between late April and mid May to lay two to four eggs. Returning each year to the same site, the male Galapagos petrel is faithful to both the female and the nest. After laying, the male takes the first incubation shift to allow the female to feed again. They take it in turns to incubate the eggs, until the chicks hatch 54 to 58 days later. Initially, the hatchlings have a covering of pale grey down on the back and white on the chest and belly. The male and female will continue to care for them for a further week, passing them regurgitated food after nibbling gently at the chick’s bills to initiate feeding (6).

The adults spend the non-breeding season out at sea, feeding during the day on squid, fish and crustacea driven to the surface by tuna and porpoises. They prey mainly on squirrel fish, flying fish, skipjack tuna and goatfish (6).

Following the proliferation of introduced cats, dogs, pigs, and black and brown rats on the Galapagos Islands in the 1980s, the Galapagos petrel has suffered a rapid decline in numbers, perhaps as much as on 80 percent reduction. Rats feed on eggs and chicks, with dogs, cats and pigs also taking adults. In addition, the Galapagos hawk, Buteo galapagoensis, has been responsible for large losses of the adult population (2).

The re-establishment of this species has also been prevented by the clearance of vegetation for agriculture, and nest site damage as a result of trampling and over-grazing by domestic goats, donkeys, cattle and horses (2).

The Galapagos Islands are a national park and a World Heritage Site, and are therefore protected. Some predator control has been carried out but a continuing programme is crucial to prevent the rat population re-establishing itself. Proposed schemes to prevent further decline of the Galapagos petrel include monitoring the breeding success of different populations under various predator control systems, in order to determine the most successful (2).

For further information on the Galapagos petrel see:

• Simons, T.R. (1985) Biology and behaviour of the endangered Hawaiian dark-rumped petrel. The Condor, 87(1): 229 – 245.
• BBC Wildlife Finder:
  http://www.bbc.co.uk/nature/species/Gal%C3%A1pagos_Petrel

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org

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

• Colony: a group of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or ‘individuals’), which are produced by budding and remain physiologically connected.
• Crustacea: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the 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, slaters, woodlice and barnacles.
• Endemic: a species or taxonomic group that is only found in one particular country or geographic area.

1. IUCN Red List (April, 2008)
   http://www.iucnredlist.org
2. BirdLife International (January, 2005)
   http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3897&m=0
3. What bird.com (January, 2005)
   http://identify.whatbird.com/obj/630/_/target.aspx
4. Global Register of Migratory Species (April, 2008)
   http://www.groms.de/
5. U.S. Fish and Wildlife Service (January, 2005)
   http://ecos.fws.gov/species_profile/SpeciesProfile?spcode=B00N
6. Simons, T.R. (1985) Biology and behaviour of the endangered Hawaiian dark-rumped petrel. The Condor, 87(1): 229 - 245.