Here we provide public access to UCE DNA sequences for all genetic samples in Byerly et al. 2022.

Co-occurring species with similar resource requirements often partition ecological niches. In the Northwest Atlantic (NWA), endangered roseate terns (Sterna dougallii) nest almost exclusively in coastal island colonies alongside common terns (S. hirundo). Roseate terns are prey specialists compared to common terns, which are opportunistic generalists; however, the two species forage on similar resources during the breeding season. The degree to which these species overlap in their adult foraging ecologies is not well understood. We compared the isotopic niches of nesting adult roseate and common terns by analyzing stable carbon (δ13C) and nitrogen (δ15N) isotopes in eggshell membrane tissues collected in 2018 and 2019 from ten colonies that span their NWA breeding range. Our aim was to characterize multi-scale patterns in isotope values, isotopic niche breadth, and isotope niche overlap between the tern species. We additionally examine subregional differences between “cold-water” colonies in the Gulf of Maine and “warm-water” colonies in Southern New England and Long Island Sound, and interannual differences between 2018 and 2019. Our results indicate similarity in isotope values and a high degree of isotopic niche overlap among adult roseate and common terns at the range-wide scale, but variable overlap at the individual colony scale. This suggests these species generally forage in isotopically similar habitats, but local resource availability influences partitioning within colonies. The isotopic niches of roseate terns were generally narrower than those of common terns, consistent with their respective specialist/generalist tendencies. Observed subregional and interannual differences were inconclusive and may reflect isotopic baseline shifts.

Co-occurring species with similar resource requirements often partition ecological niches. In the Northwest Atlantic (NWA), endangered roseate terns (Sterna dougallii) nest almost exclusively in coastal island colonies alongside common terns (S. hirundo). Roseate terns are prey specialists compared to common terns, which are opportunistic generalists; however, the two species forage on similar resources during the breeding season. The degree to which these species overlap in their adult foraging ecologies is not well understood. We compared the isotopic niches of nesting adult roseate and common terns by analyzing stable carbon (δ13C) and nitrogen (δ15N) isotopes in eggshell membrane tissues collected in 2018 and 2019 from ten colonies that span their NWA breeding range. Our aim was to characterize multi-scale patterns in isotope values, isotopic niche breadth, and isotope niche overlap between the tern species. We additionally examine subregional differences between “cold-water” colonies in the Gulf of Maine and “warm-water” colonies in Southern New England and Long Island Sound, and interannual differences between 2018 and 2019. Our results indicate similarity in isotope values and a high degree of isotopic niche overlap among adult roseate and common terns at the range-wide scale, but variable overlap at the individual colony scale. This suggests these species generally forage in isotopically similar habitats, but local resource availability influences partitioning within colonies. The isotopic niches of roseate terns were generally narrower than those of common terns, consistent with their respective specialist/generalist tendencies. Observed subregional and interannual differences were inconclusive and may reflect isotopic baseline shifts.

This data set describes blood and tissue samples collected from Mariana common moorhens from 2000-2001 in Guam and Saipan.

This data set describes blood and tissue samples collected from Mariana common moorhens from 2000-2001 in Guam and Saipan.

This data package is comprised of one table with genetic data from Brant (Branta bernicla). Data include sampling location and allele sizes of 14 microsatellite loci.

This data package is comprised of one table with genetic data from Brant (Branta bernicla). Data include sampling location and allele sizes of 14 microsatellite loci.

This data set describes accession numbers for nucleotide sequence data derived from whole mitochondrial genome and double digest restriction-site associated DNA (ddRAD).