Monthly fluctuation in the abundance of Scolopacidae and Charadriidae at Ilha Comprida beach, SP, Brazil

Abstract

We recorded the frequency of occurrence and monthly fluctuations of Charadriidae and Scolopacidae along a 70km transect of beach between Boqueirão Sul and Boqueirão Norte north of Comprida island, São Paulo State over a 1-year period (Jan - 2010 to Dec - 2010). A total of 12.153 shorebirds were recorded. The greatest abundance occurred between October and April and the lowest occurred between May and September. The most abundant of the 20 species recorded were Charadrius semipalmatus, Charadrius colaris,Vanellus chilensis and Tringa flavipes. The least abundant wereTryngites subruficolis, Limosa haemastica, Tringa melanoleuca and Actitis macularia. Sixteen species were migrants from the Northern Hemisphere, two were migrants from the Southern Hemisphere, and two were residents. Seven species were recorded regularly, five were recorded sporadically, and eight were recorded occasionally. Four Nearctic species were recorded in June and July most likely indicating the presence of non-breeding immature. The number of species and the number of individuals probably fluctuated due to migration or movements between neighbouring beaches. The Comprida Island beach is important migration stopover and wintering sites for many shorebirds in south São Paulo and should be a focus of conservation efforts, especially given the increasing development pressure that threatens these areas.