Uso de habitats e sazonalidade de aves limícolas no Canal da Raposa, Ilha de São Luís, Maranhão, Brasil.

Abstract

The objective of this work was to characterize use of habitat and seasonality of shorebirds in Raposa s Channel, North of São Luís Island, Gulf of Maranhão. The censuses of shorebirds occurred during two consecutive weeks of each month between February and November 2006. Three areas (each one with 3ha) were selected for censuses, considering the type of flat (mud, sand-mud, sand). The censuses were taken during one spring tide and during one neap tide of each month. In foraging, 17407 shorebirds were observed during the study. The highest density of shorebirds feeding was in the mudflat (180.95 ind/ha), then sand-mudflat (100.25 ind/ha) and sandflat (27.10 ind/ha). Calidris pusilla was the most abundant species in Raposa s Channel (n = 8922) and in the mudflat (n = 7578). In sand-mudflat, Tringa semipalmata was the most abundant species (n = 1270) and in the sandflat it was Pluvialis squatarola (n = 130). Tringa semipalmata was the most abundant species in the roost area (n = 788). The highest density of shorebirds feeding was observed during neap tides. The high density of shorebirds observed probably might be due to the study area to form a mosaic of habitats still conserved. Pluvialis squatarola, Numenius phaeopus, Tringa semipalmata, Calidris canutus, A. interpres and Charadrius semipalmatus presented this seasonal pattern: high density between February and April, decreases between May and July and increase in density between August and November. Calidris pusilla and differed for presenting increases in density in July; Limnodromus griseus had presented high density only since August and Charadrius collaris had increases in density between February and July, and decreases between August and November. The seasonal patterns demonstrated the importance of Raposa s Channel as stopover area for some species and winter area for others shorebirds species. Thus, the identification and characterization of Raposa s Channel as important wintering area for migratory shorebirds is fundamental to create conservation plans for north brazilian coast, in order to maintaining the shorebirds populations at long term in nature.