|Central coordinates||15o 23.00' West 10o 38.00' North|
|IBA criteria||A4i, A4ii|
|Altitude||0 - 12m|
|Year of IBA assessment||2001|
Site description Ile Alcatraz (0.75 ha) is a lateritic rock islet on the continental shelf of the Atlantic Ocean, 40 km south-west of Iles Tristao (IBA GN004). The Ile de Naufrage (0.25 ha) is a sandbank 2 km south-west of Ile Alcatraz which is exposed even at high tide. Ile Alcatraz is unvegetated and covered with guano to a depth of about 3 m, which is the cause of its white appearance. The Ile de Naufrage is also unvegetated and reaches a maximum height of c.3 m above high water. The intertidal area is mainly sandy.
Key Biodiversity See Box for key species. Ile Alcatraz holds the only known breeding colony of Sula leucogaster between Cape Verde and São Tomé and Príncipe. There is breeding activity throughout the year. The Ile de Naufrage provides a roost for thousands of terns including Sterna maxima, S. hirundo, S. sandvicensis, S. albifrons and Chlidonias niger.
Non-bird biodiversity: Among mammals, the dolphin Sousa teuszi (DD) and the sirenian Trichechus senegalensis (VU) are reported from the area; sea-turtles also occur.
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Brown Booby Sula leucogaster||breeding||1988||3,000 breeding pairs||-||A4ii||Least Concern|
|Royal Tern Thalasseus maximus||winter||1988||3,000 individuals||-||A4i||Least Concern|
|2001||medium||not assessed||not assessed|
|Good - based on reliable and complete / representative data|
|Pollution||industrial & military effluents - oil spills||likely in long term (beyond 4 years)||some of area/population (10-49%)||slow but significant deterioration||medium|
|Protected area||Designation||Area (ha)||Relationship with IBA||Overlap with IBA (ha)|
|Ile Alcatraz||Wetlands of International Importance (Ramsar)||1||is identical to site||1|
|Land-use||Extent (% of site)|
|nature conservation and research||-|
References Altenburg and van der Kamp (1991a, b), Jones (1993).
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Recommended citation BirdLife International (2015) Important Bird and Biodiversity Area factsheet: Ile Alcatraz et Ile du Naufrage. Downloaded from http://www.birdlife.org on 02/12/2015
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