TOWARD CONSERVATION OF MIDCONTINENTAL SHOREBIRD MIGRATIONS

Shorebirds represent a highly diverse group of species, many of which experience tremendous energy demands associated with long-distance mig ratory flights. Transcontinental migrants are dependent upon dynamic f reshwater wetlands for stopover resources essential for replenishment of lipid reserves and completion of migration. Patterns of shorebird m igration across midcontinental wetlands were detected from migration r eports to American Birds and information provided by U.S Fish and Wild life Service national wildlife refuges. Patterns in species compositio n and abundance varied geographically, emphasizing the uniqueness of d ifferent regions to migrating shorebirds. Smaller species and neotropi cal migrants moved primarily across the Great Plains, whereas larger s pecies and North American migrants predominated in assemblages in the intermountain west Shorebirds were broadly dispersed in wetland habita ts with dynamic water regimes. Whereas populations of shorebirds in co astal systems appear to concentrate at sites of seasonally predictable and abundant food resources, we propose that transcontinental shorebi rds disperse and use wetlands opportunistically. This migration system exemplifies the need for large-scale, coordinated regional management efforts that recognize the dynamic nature of ecosystem processes.