Abstract

GUEVARA-MEDINA, Miguel Ángel; CASTILLO-GUERRERO, José Alfredo  and  GONZALEZ-BERNAL, Marco Antonio. Presence and abundance of avian species on Farallón de San Ignacio Island, Sinaloa. Huitzil [online]. 2008, vol.9, n.2, pp.20-28. ISSN 1870-7459.

To determine the presence and abundance of avian species that use Farallón de San Ignacio Island, Sinaloa, we documented the birds observed during 46 visits of five days on the island between 2003 and 2008. We registered 57 bird species. Five marine species regularly nested on the island: Sula nebouxii, S. leucogaster, Phaethon aethereus, Phalacrocorax auritus and Larus heermanni. In 2008, one raptor, Falco peregrinus, nested on the island. Added to which, we observed 24 species of non-nesting aquatic birds, and 27 species of terrestrial birds. The breeding season for nesting birds coincided with the period of high primary productivity in the Gulf of California. The island is an important nesting site for P. aethereus, and is one of the two most important colonies in the Gulf of California. The island is only marginally important for the rest of the nesting species as other islands have larger colonies. Due to the lack of vegetation, terrestrial birds use the island only occasionally and for brief periods, particularly neotropical migratory species during the migration. On comparing with other islands in the southern part of the Gulf of California, Farallón de San Ignacio exhibited greater species richness than expected for its size. This discordance could be explained by the greater sample effort, and the existence of a larger quantity of terrestrial bird species using coastal habitats in Sinaloa that may occasionally disperse to nearby islands.

Keywords : Islands; southern Gulf of California; Bird list; Phaethon aethereus; reproduction of marine birds.

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