Curtiss, D. and Pierce, A.R., 2016. Evaluation of wintering waterbird habitats on Louisiana barrier islands.
Louisiana's barrier islands provide unique habitats for waterbirds throughout the year. Unfortunately, barrier islands such as those within the Isles Dernieres Barrier Island Refuge (IDBIR) are rapidly degrading, and critical waterbird habitats are disappearing. The majority of waterbird research projects in the northern Gulf of Mexico have focused on important breeding habitats, but little information exists on preferred habitats during the nonbreeding wintering period. The goal of this study was to identify important waterbird habitats on barrier islands during the nonbreeding period to enhance barrier island management for year-round use by waterbirds. Biweekly surveys were conducted at the IDBIR during the 2010–2011 and 2011–2012 nonbreeding seasons to determine waterbird use of beach habitats. Habitat maps of the IDBIR were also created to calculate bird densities and species richness among habitat types, including bayside intertidal, flats, gulfside intertidal, nonintertidal, and rock structures. This study also quantified availability of food resources by collecting benthic core samples from substrates at each habitat type. Forty-seven waterbird species were observed during waterbird surveys. Wine Island had the greatest species richness and bird density (5.5 species/ha and 325.6 birds/ha) among the islands, as well as the greatest density of foraging waterbirds. Rock structures and gulfside intertidal habitats had the greatest species richness and bird densities among habitat types. East and West Raccoon islands and intertidal habitats had the greatest availability of invertebrate prey. There was a moderate correlation (r2 = 0.32) between invertebrate biomass and abundance of foraging shorebirds. It is recommended that future restoration projects provide wide, expansive intertidal habitats to enhance critical wintering habitats for waterbirds.
