Community composition and migration chronology of shorebirds using the saline lakes of the Southern Great Plains, USA

Shorebirds migrating through the Southern Great Plains (SGP), USA, use freshwater playas and saline lakes as stopovers. The importance of playas is well documented, but the role of saline lakes is not clearly understood. During 2002 and 2003, we conducted surveys to determine the extent to which the saline lakes serve as stopovers. Twenty-eight species were recorded, and total seasonal abundance ranged from 6779 to 29,924 birds. Potential shorebird abundance for extant saline lakes was estimated at 37,000-71,000 shorebirds annually. American Avocets (Recurvirostra americana), Western Sandpipers (Calidris mauri), Baird's Sandpipers (C. bairdi), Least Sandpipers (C. minutilla), Snowy Plovers (Charadrius alexandrinus), Killdeer (Charadrius vociferus), and Wilson's Phalaropes (Phalaropus tricolor) were the most abundant species. Community composition of shorebirds differed between saline lakes and regional freshwater playas. Peak spring abundance was generally in April, whereas summer/fall migration was more protracted and shorebird abundance peaked during 6-8 weeks in August and September. Migration chronologies differed among morphologically similar species, and among representative species from different guilds. Such patterns of temporal separation permit partitioning of resources by shorebirds migrating through the SGP. The saline lakes of the SGP should be regarded as stopover sites of regional and international value. To ensure that saline lakes function as stopovers and to help maintain those unique communities that inhabit them, conservation of saline lakes should focus on preserving spring flows and conserving water.