Use of saltworks by Red Knots at Guerrero Negro, Mexico

Monthly counts of Red Knots using a low salinity concentration pond at the Guerrero Negro saltworks, Baja California, Mexico during Aug. 2005 to April 2006 showed peaks of 835 in Aug. and 2,907 in Oct. Saltworks are an unusual habitat for knots and we suppose that greater numbers were using the species’ more typical intertidal habitats in the adjacent Ojo de Liebre Lagoon. Nevertheless the count of 2,907 is nearly three times any other count of knots in the whole of Mexico. When peak numbers occurred in Oct. 2005, the abundance of knots in the saltworks was significantly and positively correlated with the height of the tide in the adjacent lagoon suggesting that some birds were feeding in the intertidal habitats over low water and moving into the saltworks at high tide. However, up to 1,500 were present in the saltworks at low tide and many fed there.