Habitat Use by Coastal Birds Inferred from Stable Carbon and Nitrogen Isotopes

Conservationists need to know the degree of habitat fidelity for species of conservation concern. Stable Isotope Analysis in R quantified the contribution of terrestrial vs. saltmarsh primary production sources to terrestrial passerine food webs from four habitats of Sapelo Island, Georgia (USA), saltmarsh, maritime scrub-shrub, maritime broadleaf (oak), and maritime narrowleaf (pine) forests, using delta C-13 and delta N-15. Models suggested Northern Parula (Parula americana) in oak forests, White-eyed Vireos (Vireo griseus) in shrub, and Brown-headed Nuthatches (Sitta pusilla) in pine forests derived most of their food from habitats they occupied (53-100%). Saltmarsh provided 47-94% of Painted Bunting (Passerina ciris) food sources, supporting previous findings by Springborn and Meyers (2005). Thus, Painted Bunting conservation in the Southeastern USA should focus on Springborn and Meyers' suggestion of maritime scrub-shrub habitat and forests with < 75% canopy, > 50% ground cover, and patches of shrubs that are within 700 m of saltmarsh.