Shorebirds seasonal abundance and spatial distribution patterns at Samborombón Bay, Argentina.

MARTÍNEZ CURCI N.S.; ISACCH JP; BLOCK C.; PEDRANA J.; AZPIROZ AB

Virginia

Congreso; VI Western Hemisphere Shorebird Group Meeting; 2015

Virginia Tech

Samborombón Bay is one of the most important sites for shorebirds identified in the Americas. However, information about birds abundance and distribution is scarce and outdated. For example, the last comprehensive censuses were conducted more than 20 years ago during austral summer, autumn and spring, seasons in which the shorebirds assemblages is dominated by Nearctic species. Additionally, there is no previous information about austral winter, when Neotropical migrants and resident species are dominant. Our aim was to determine the total shorebirds numbers using Samborombón Bay, and the seasonal variation in abundance and spatial distribution patterns. To achieve this we conducted four aerial censuses, one in each season of 2014, covering the 150 km of extension of Samborombón Bay. We observed a total of 9710 shorebirds during austral summer, 12475 during autumn, 4300 during winter and 31700 during spring. These results were about the same order of magnitude than those observed in past decades. Abundance data were georeferenced and added to a geographic information system together with biological, physical and landscape information from the study area. Based on these information we generated distribution maps, identifying the main factors that determine distribution and abundance patterns at Samborombón Bay.