Galapagos Petrel

The endemic Galapagos Petrel (Pterodroma phaeopygia) is a sea bird in danger of extinction. Their critically endangered status places them as a high priority in the conservation efforts supported by the Charles Darwin Foundation (CDF).

Contents 1 Unique to Galapagos 2 Vulnerability 3 CDRS research activities

Unique to Galapagos

Adult Galapagos Petrels have dark brownish-black upperparts and white lower parts, with a white forehead and long, narrow wings. This coloring is quite distinctive when the petrel is in flight. The bill is thick and black.

The Galapagos Petrel breeds in the Miconia zone in the highlands of San Cristóbal, Santa Cruz, Santiago and Floreana Islands. These four populations vary in size, and breed at different times of the year. The species mate for life and return to the same burrow each year. They nest in moist soils in sink holes and gullies. A single white egg is laid in a deep burrow. Both parents incubate the egg and feed the nestling regurgitated fish, crustaceans and squid mixed with oil. After leaving the nest, the Galapagos petrel takes 5-6 years to reach maturity, and then searches for partner and a suitable place to burrow.

Vulnerability

In Hawaii, the Hawaiian petrel (Pterodroma sandwichensis) is on the brink of extinction, while in Galapagos major efforts are underway to save the Galapagos Petrel. This species is listed as Critically Endangered by the IUCN since 1994.

Populations of Galapagos Petrels were larger in the past. However, many nesting sites were lost when man began to use the rich volcanic soil areas of the highlands for growing crops and rearing livestock. These birds are also threatened by many introduced predators. Rats and pigs eat the eggs and nestlings and, along with dogs and cats, kill the chicks and adult birds. Invasive introduced plants such as red quinine are spreading and are rapidly altering the birds' nesting habitat with unpredictable consequences.

CDRS research activities

In 1980, the Galapagos National Park Service (GNPS) and CDF scientists began an intensive predator control program at the petrel's main nesting colonies on Floreana and Santa Cruz. The program is ongoing and involves control of predators, monitoring nests, locating new nests, and banding.

The project is enabling the petrel to breed, however the protection nesting colonies must be maintained indefinitely. Black rats are will be difficult to eradicate completely, although rats and cats are the next targets for major CDF/GNPS control programs in Galapagos.

Whilst the project has successfully enhanced breeding success, fledglings must then survive to adulthood and breed. In 1997, analysis of banding data showed out of more than 1,000 juveniles banded in the past 35 years, less than 3% returned to the colonies on Floreana and Santa Cruz.

To quantify the effects of low juvenile recruitment, further modeling needs to combine this data with adult survivorship, and fledgling success. This may indicate possible causes of post-fledging, pre-breeding loss. Juvenile mortality may occur at sea, making it difficult to counteract, particularly if it occurs outside the Marine Reserve. There is no doubt, however, that the present program is enhancing the survival of this species.

In 2005, exploration for potential Galapagos petrel nesting sites found around 300 new nests on Santa Cruz Island, almost doubling the known population. This suggests that they may be extending their nesting areas. The newly identified colonies are now benefiting from the breeding protection program. Other nesting colonies need to be looked for and protected on San Cristóbal and Isabela Islands. On San Cristóbal, only 30 nests have been found, and on Isabela, two nests were located on Alcedo Volcano in 2002.