J. Field Ornithol. 77(4):372–383, 2006 DOI: 10.1111/j.1557-9263.2006.00067.x Community composition and migration chronology of shorebirds using the saline lakes of the Southern Great Plains, USA Adrian E. Andrei, 1,4 Loren M. Smith, 1 David A. Haukos, 2 and James G. Surles 3 1 Department of Range, Wildlife, and Fisheries Management, Texas Tech University, Lubbock, Texas 79409, USA 2 U.S. Fish and Wildlife Service, Department of Range, Wildlife, and Fisheries Management, Texas Tech University, Lubbock, Texas 79409, USA 3 Department of Mathematics and Statistics, Texas Tech University, Lubbock, Texas 79409, USA Received 25 May 2006; accepted 10 September 2006 ABSTRACT. 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. SINOPSIS. Composici ´ on de la comunidad y cronolog´ ıa migratoria de playeros que utilizan los lagos salobres de las grandes planicies del sur de los EUA Los playeros que migran a trav´ es de las grandes planicies del sur de los Estados Unidos, utilizan como lugares de parada playas de agua fresca y lagos salobres. La importancia de las playas ha sido muy bien documentada, pero no se entiende bien el rol que puedan tener los lagos salobres. Durante el 2002 y el 2003, realizamos trabajos para determinar hasta que punto los lagos salobres serv´ ıan como lugares importantes de parada. En estos, enontramos la presencia de 28 especies y una abundancia que var´ ıa entre 6779 y 29,924 aves. El uso potencial de estos lagos salinos es de 37,000 a 71,000 individuos. Las especies m´ as abundantes en este tipo de habitat resultaron ser Recurvirostra americana, Caladris mauri , C . bairdi , C . minutilla, Charadrius alexandrinus y Phalaropus tricolor . La composici´ on de playeros result´ o ser diferente en las playas de agua fresca y en los lagos salobres. El pico en la abundancia durante la primavera, se llev´ o a cabo generalmente en Abril, mientras que el pico de los migrantes de verano/oto˜ no ocurri´ o por un periodo de 6–8 semanas de agosto a septiembre. La cronolog´ ıa migratoria tiene sus diferencias entre especies de morfolog´ ıa similar, al igual que en especies de otros grupos. Este patr´ on de separaci´ on temporera, permite la repartici´ on de recursos entre las aves que migran a trav´ es de las grandes planicies. Los lagos salobres en dicha ´ area deben ser considerados como lugares de paradas de gran importancia a nivel nacional e internacional. Para asegurar que dichos lagos salobres mantengan su funci´ on como lugares de paradas, la conservaci´ on de los mismos debe enfocar el preservar el flujo de agua a estos durante la primavera. Key words: migration chronology, playas, saline lakes, shorebirds, Southern Great Plains Many shorebirds migrate through interior North America between Arctic nesting grounds and wintering areas in Central and South America (Morrison 1984, Skagen and Knopf 4 Corresponding author. Email: andreia@lincolnu. edu 1993, Davis and Smith 1998a). These migrants need to replenish and accumulate energy reserves (Morrison 1984, Senner and Howe 1984, Myers et al. 1987) at stopover sites along the migration route (Skagen and Knopf 1993). Millions of shorebirds use the 25,000 playas of the Southern Great Plains (SGP) (Davis and Smith 1998b) as important “stepping stones” (Skagen and Knopf C  2006 The Author(s). Journal compilation C  2006 Association of Field Ornithologists 372