Habitat use and selection of black scoters in southern New England and siting of offshore wind energy facilities

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The southern New England continental shelf is an important region for black scoters (Melanitta americana) during winter and migratory staging periods and a priority area for developing offshore wind energy facilities. However, little is known about the migration phenology and habitat use of black scoters in this portion of their range and this information is necessary to assess potential risks to black scoters during the marine spatial planning process. In this regional black scoter study over 2 winters, we used satellite telemetry and spatial modeling techniques to estimate migratory timing and length of stay, quantify winter home range size and site fidelity between winters, examine key habitat characteristics associated with core-use areas, and map relative probabilities of use across a 3,800-km2 marine spatial planning area for 2 proposed offshore renewable energy facilities. Black scoters spent nearly 5 months in southern New England, with wide variation among individuals in the size of winter utilization distributions (range 16-12,367 km2). Approximately 50% of the tagged birds returned to southern New England during the subsequent winter and had variable fidelity to core-use areas occupied the previous winter. During both winters, black scoter core-use areas were located closer to shore, at shallower water depths, with coarser sediment grain size and higher probability of hard-bottom occurrence relative to available areas. Resource selection functions classified the majority of a nearshore 5-turbine, 34-km2 renewable energy zone off Block Island as high probability of use by black scoters, whereas an offshore 200-turbine, 667-km2 federal lease block zone was classified as low to medium-low probability of selection. Wind energy facilities, such as the Block Island site, constructed in relatively shallow (<20 m deep), nearshore habitats (<5 km) over hard-bottomed or coarse-sand substrate could displace some foraging black scoters wintering in this region, whereas the larger federal lease block zone located farther offshore is more likely to affect scoters dispersing among core-use areas and during migration between wintering and breeding grounds. © 2014 The Wildlife Society.

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Journal of Wildlife Management