Habitat use by breeding willets in the northern Great Plains

Catoptrophorus semipalmatus defended multipurpose territories (mean 44 ha) including sizeable upland components. Most breeding pairs (90%) and broods (70%), however, were sighted in or near wetlands where they fed. Willets defended areas with greater densities and diversity of wetlands than generally available across the study area. Willet pairs were most often observed in semipermanent wetlands, but based on use vs. availability, willets preferred ephemeral, temporary, seasonal, and alkali wetlands over semipermanent and permanent wetlands. Wetlands used by willets had significantly greater proportions of more open cover types than those not used. Within used wetlands, willets made disproportionately frequent use of lightly vegetated sites. Willets made little use of upland habitats, except for nesting. Upland sites used by pairs were dominated by short (<15 cm) native grass cover. Willet defense of large, multipurpose territories seems related to limited wetland foraging habitats and possible advantages gained by spacing nests to reduce predation. -from Authors