SHOREBIRD SURVEYS IN ENSENADA PABELLONES AND BAHIA SANTA MARIA, SINALOA, MEXICO: CRITICAL WINTER HABITATS FOR PACIFIC FLYWAY SHOREBIRDS

On 6-9 December 1993 andc 14-18 February 1994 ground surveys of shorebirds were con- ducted in Ensenada Pabellones and Bahia Santa Maria, Sinaloa, Mexico. These were the first comprehensive ground surveys of shorebirds conducted in western Mexico. Twenty-nine species of shorebirds were recorded. The composition was characterized by those species spending their non-breeding period on the Pacific Coast of North America. Total numbers of shorebirds estimated were 340,063 birds (December) and 405,483 birds (Feb- ruary) in Ensenada Pabellones and 248,044 birds (December) and 389,841 birds (February) in Bahia Santa Maria. Western Sandpiper (Calidris mauri) comprised 82% of shorebirds present in both bays. American Avocet (Recurvirostra americana; 6% average total), dowitchers (Limnodromus spp.; 6% average total), and Least Sandpiper (Calidris minutilla; 3% average total) were also abundant. These bays hold approximately 30% of the shorebirds wintering in Pacific coastal regions of North America. Using Western Hemisphere Shorebird Reserve Network criteria, both bays are of international importance for shorebirds. Ensenada Pabellones is of regional importance for American Avocets supporting nearly 10% of the total world population. Both bays would qualify as wetlands of international importance as defined by the Ramsar Convention on international wetlands. Received 28 Aug. 1997, accepted 18 April 1998.