DYNAMIC SURFACE WATER DISTRIBUTIONS MEDIATE MOVEMENTS OF NON-BREEDING SHOREBIRDS IN THE CENTRAL VALLEY OF CALIFORNIA

Blake Barbaree; Point Blue Conservation Science; bbarbaree@pointblue.org; Matthew E. Reiter, Catherine M. Hickey, Gary W. Page, Nathan K. Elliot, Danica Shaffer-Smith, Mark D. Reynolds

Movements by migratory shorebirds are inherently linked to dynamic water distributions. Characterizing this relationship when shorebirds are not breeding or migrating can highlight effects of landscape management strategies on shorebird populations as well as provide simple guidelines for conservation solutions that benefit people and wetland-dependent wildlife. We tracked radio-tagged dunlin (Calidris alpina) and long-billed dowitchers (Limnodromus scolopaceus) in the Central Valley of California to compare movements between shorebirds wintering in regions with differing amounts and configurations of water on the landscape and investigated associations between movements and variability in landscape structure at multiple temporal and spatial scales. Shorebirds using a region with a widespread but highly variable water distribution moved between regions more often and had longer movements on average than those wintering in a region characterized by a single, mostly contiguous wetland complex with relatively stable landscape structure. Longer movements were associated with decreasing average water availability on the landscape as well as increasing patch size and decreasing aggregation of reliable surface water. Humans can mediate the energetically costly movements of shorebirds by reliably flooding individual wetlands and agricultural lands and limiting variability in the configuration of open water. The creation, restoration, and maintenance of flooded wetlands and agricultural lands will have high conservation value, particularly during March and April in the Central Valley, along likely flight corridors, in locations with frequent past flooding events, and areas that increase the spatial aggregation of surface water.

Ecology and Conservation of Birds III