Patterns of occurrence and abundance of land birds on Saliaca Island, Sinaloa, Mexico

Abstract

WE DETERMINED THE ABUNDANCE AND TAXONOMIC COMPOSITION OF LAND-BIRDS IN SALIACA ISLAND, SINALOA, MEXICO, BY MEANS OF POINT COUNTS DURING 3 SAMPLING PERIODS (SUMMER, AUTUMN AND WINTER) AND 3 TYPES OF HABITAT (THORN FOREST, MANGROVE AND DUNE). WE OBSERVED 82 SPECIES, WHICH IS GREATER THAN THE NUMBER REPORTED FOR ANY OTHER ISLAND OF THE GULF OF CALIFORNIA. THE SPECIES RICHNESS AND ABUNDANCE WERE GREATER IN AUTUMN (59 SPECIES AND 9.2 ± 1.2 BIRDS PER POINT COUNT) AND WINTER (48 AND 7.5 ± 0.9) THAN IN SUMMER (33 AND 5.2 ± 0.3), A PATTERN RESULTING FROM THE ARRIVAL OF NEOTROPICAL MIGRANTS. WITH REGARD TO DIFFERENCES BY HABITAT, THE GREATEST RICHNESS AND ABUNDANCE OCCURRED IN THE THORN FOREST (60 SPECIES AND 9.3 ± 0.9 BIRDS PER POINT), FOLLOWED BY MANGROVE (16 AND 3.3 ± 0.8) AND DUNE (3 AND 1.0 ± 0.2), WHICH IS AGREEMENT WITH THE HIGHER COMPLEXITY OF VEGETATION STRUCTURE AND THE GREATER AREA OF THORN FOREST. SALIACA ISLAND COULD REPRESENT A RELICT OF THE COASTAL REGIONAL HABITAT, WHICH ENHANCES ITS CONSERVATION AND PROTECTION VALUE.