Juan Fernandez Petrel

The Juan Fernández petrel, a large gadfly petrel, is a remarkable seabird with a length of 43 cm and a wingspan stretching between 95 to 97 cm. It weighs approximately 500 grams. This species is adorned with dark brownish-grey upperparts and a distinctive black M-shaped marking across its wings when extended. Its underparts are a stark white, contrasted by the black-edged underside of its wings. The face is predominantly white, complemented by a black "cap" that extends below the eyes. The petrel's feet are a striking yellow, darkening to brown at the tips, and its bill is black with a hooked tip, characteristic of its family, housing the unique tubular nostrils of the Procellariiformes.

Identification Tips

When observing the Juan Fernández petrel, look for the contrasting dark M-shaped marking on the upper wings and the white face with a black cap extending below the eyes. The yellow feet with dark tips and the black, hooked bill are also key features to distinguish this species from others.

Habitat

The Juan Fernández petrel is known to nest at high elevations above 750 meters on ridges within the Juan Fernández Archipelago.

Distribution

This petrel breeds exclusively on Isla Alejandro Selkirk in Chile and forages in surrounding waters, including Isla Robinson Crusoe and coastal Chile. Outside the breeding season, it ranges as far north as the Hawaiian Islands and has been recorded as a vagrant in locations such as Australia, the Chatham Islands, Fiji, and the United States.

Behaviour

The Juan Fernández petrel is a social bird, often found in flocks with pink-footed shearwaters and other seabirds. It is a skilled navigator of the equatorial currents and counter-currents during its non-breeding season.

Breeding

The breeding ritual of the Juan Fernández petrel involves digging a 2-3 meter burrow on high elevation ridges to lay a single white egg in mid-November. Both parents share the duty of incubating the egg for about 60 days. The chick hatches in mid-February and is nurtured by both parents for 90-100 days before fledging in May. The chick remains safely underground in the burrow until it is fully feathered and has reached fledgling mass, subsisting mainly on a diet of regurgitated fish and squid provided by its parents.

Diet and Feeding

The diet of the Juan Fernández petrel chick primarily consists of regurgitated fish and squid, indicative of the adult's diet at sea.

Conservation status

The Juan Fernández petrel is currently classified as Vulnerable on the IUCN Red List. The species faces threats from introduced predators such as cats and rats, and to a lesser extent, habitat loss due to introduced herbivores like goats. The breeding population was estimated at 1 million pairs in 1985-86, with a global estimate of 3-5 million birds.