petrel blanco de Juan Fernandez (Pterodroma externa), volando frente a Rodríguez o playa del buque varado
Image by Pato Novoa
Classified as Vulnerable (VU) on the IUCN Red List 2007 (1)
Petrels are oceanic birds, with large webbed feet adapted to their aquatic lifestyle, and their wings allow them to fly long distances over the ocean and withstand powerful storms. The plumage of the Juan Fernández petrel is brownish gray on the back, with a black mark in the shape of M through the extended wings. The belly is white, with the underside of the wing edged in black. The face is white, ‘with a hat’ black extending below the eyes. The black bill has a hooked tip and houses tubular nostrils are a unique feature of Procellariiformes, also known as the ‘tubenoses’ (4).
The Juan Fernandez petrel breeding only on Alejandro Selkirk Island, part of the Juan Fernandez Islands archipielgo, Chile. When not breeding can be found on tropical and subtropical waters of the Pacific Ocean, north to Hawaii and the Far East yan as New Zealand and Australia from East (2)
Juan Fernandez petrel nesting endemic of Alejandro Selkirk Islandis a highly pelagic species and sea that is often found in emergency areas, and rarely comes to land except to breed. Is played by holes on slopes and cords fern forest or grassland, on high ground, between 600 and 1,000 meters, (2).
Juan Fernández petrels spend most of his life out over the oceans, where they search for food fish and squid (2). They are often found in emergency areas, where cold water, and rich in nutrients rises to the surface, resulting in abundance of prey. They can be seen feeding along with other seabirds (2), or from time to time around fishing boats (2). Juan Fernandez petrel often depends on subsurface predators such as tuna and yellowfin cetátaceos that lead their prey to the surface (3).
Juan Fernández petrels return to their secluded island to breed in October and November (2), where they form breeding colonies. Females lay a single egg in a burrow chicks born a gray, soft in February and March. The chicks are hatched for three weeks before being left unattended during the day while their parents go off to feed. The adults return to their burrows at dusk where waiting for their offspring. Most of petrel chicks are covered with feathers in May and June.
The Juan Fernández petrel appears face their greatest threats over his tiny farming on the island, where numerous species cause extensive damage to natural ecosystems, and potentially affect the petrel. Rats, feral cats and coatis pose a significant threat to Juan Fernández petrel predation, rabbits compete for burrows, and burrows and cattle trampling can degrade breeding habitat suitable for grass. Juan Fernandez petrel may also be affected by human disturbance on their breeding grounds, and the fishwife industry may indirectly affect the petrel by reducing the numbers of subsurface predators such as tuna yellowfin.
Since 1935, the Juan Fernández Islands were designated a national park and in 1977 they were declared a biosphere reserve. However, these measures have not offered any protection against predators abundant presented affecting the native inhabitants of the island. There were attempts to control these invasive species, in 1983 the sheep was successfully removed from Alejandro Selkirk Island, and the Project Co-Holland Juan Fernandez implemented various programs to control exotic plant species, goats, and rabbits. Juan Fernández Islands Conservancy (JFIC) aims to protect the long-term health of the archipelago by a combination of basic research, applied conservation and environmental education in collaboration with local residents. In 2001, JFIC began a research program focused on four pelagic seabirds, including petrel, investigating their basic ecology and factors potentially important for future conservation measures (5). However, without eliminating the threats posed by invasive species, any other conservation measure is probably fruitless, and so believes that efforts JFIC complete removal (unlike control programs) are required (5). Improving the yellowfin tuna fishwife industry to ensure sustainability also probably benefit from Juan Fernández petrel (3).
Translated from "Juan Fernández petrel (Pterodroma externa)" by Peter Odum, .
www.arkive.org / juan-fernandez -petrel/pterodroma-externa/v …
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