Prey and Habitat Influences the Movement of Clapper Rails in Northern Gulf Coast Estuaries

Abstract

Loss and modification of tidal marsh habitat has contributed to the decline of marsh bird species. For many marsh birds that inhabit tidal ecosystems, little information exists on habitat use, particularly in relation to movement and response to prey availability. In this study, radio-telemetry was used to investigate home range size, movement patterns and response of Clapper Rails (Rallus longirostris) to prey availability within tidal marshes in coastal Mississippi. Mean fixed kernel 95% home range for breeding Clapper Rails was 1.37 ha ± SE 0.27 (N = 10 birds) with a 50% core use area 0.32 ha ± SE 0.07 (N = 10 birds), which are estimates similar to those obtained throughout this species' range. The extent of Clapper Rail movements during the incubation period was negatively correlated with density of fiddler crab burrows within 50 m of nest sites. Clapper Rails' use of marsh edge decreased relative to tidal height. Use of this habitat type may have been further restricted during the first few weeks of the parental-care period when adults were caring for recently fledged young. Collectively these results illustrate the importance of edge and interior marsh habitats and may provide an explanation for the variation in Clapper Rail densities found within and between tidal marsh systems.