A year-long survey on Nearctic shorebirds in a chain of coastal lagoons in Northern Rio de Janeiro, Brazil

This present work aims to provide the very first data on abundance of migratory shorebirds in coastal lagoons of northern Rio de Janeiro State; to assess seasonal patterns; to test the null hypothesis that there are no significant differences in abundance between areas inside and outside the Restinga de Jurubatiba National Park boundaries; and to compare abundance results with reports from others stopovers on the coast of Brazil. Data on density, mean counts and maximum number of individuals were obtained monthly at counting points, between May 2012 and April 2013. We recorded 16 Nearctic shorebirds species. Mean density was 327 birds/km² and mean count was 1,188 individuals. The maximum number recorded was 6,133 shorebirds, in April 2013. The most abundant species were Calidris fuscicollis (99 birds/km²), Calidris alba (80 birds/km²) and Tringa flavipes (66 birds/km²). These species showed opposing trends of abundance pattern along months, probably due to interference competition. On average, shorebirds occurred with greater densities outside than inside the Restinga de Jurubatiba National Park boundaries, with 42.3 birds/km² and 29 birds/km², respectively. In comparison with other 17 stopovers in the Brazilian coast, the surveyed coastal lagoons occupied the seventh position in an abundance ranking. Finally, the study site meets at least two Ramsar Convention criteria for inclusion in the list of wetlands with international importance.