Estratégias de forrageamento e evitação de predadores em Charadriidae e Scolopacidae na Baía de Todos os Santos, Bahia, Brasil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Shorebirds (Charadriidae and Scolopacidae) are a notable component of coastal ecosystems, especially of bays and estuaries. The great majority of these species is migratory, conducting long trips between Arctic and Sub-arctic breeding grounds and temperate and tropical wintering grounds. My general objective of this thesis was to analyze the foraging and predator avoidance strategies in shorebirds in Baía de Todos os Santos, Bahia, Brazil. Considering the high energetic demands of these birds in their wintering grounds, I analyzed the influence of abiotic (e.g. tidal cycle, sediment type and coastal proximity) and biotic (e.g. potential predators and prey availability) factors on the behaviour and on the use of the intertidal flats by feeding shorebirds, from December 2006 to March 2009. Experiments and observations in the field confirmed that the tidal cycle influenced the foraging behaviour of the birds. Some shorebird species intensified foraging activity during passage of the tidal line, while others did so during the low tide. Shorebirds did not exhibit antipredator behaviours predicted in theory, such as avoidance of the shoreline or flocking/flight in the presence of a raptor. Moreover, human recreation activities were more threatening to the shorebirds than shellfishing activity. Association analyses between birds densities and environmental factors revealed that the use of the intertidal flats by feeding shorebirds was driven, particularly, by food availability and sediment type. The maintenance of the diversity and the quality of habitats of this bay is crucial to meet the species-specific requirements of 10 migratory Charadriidae and Scolopacidae species and one resident population of Charadrius wilsonia.

ASSUNTO(S)

ecologia comportamental waders group life Área de invernagem limícolas charadriiformes marisqueiros vida em grupo ecologia wintering area charadriiformes behavioral ecology shellfish

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