This dataset shows "core" habitat for Long-tailed Ducks, represented as concentrations in abundance distributions based on a dataset that originated with the Massachusetts Audubon Society (Mass Audubon) with additional analysis by the Massachusetts Natural Heritage and Endangered Species Program (NHESP). Mass Audubon provided radio telemetry data from Long-tailed Ducks tagged in Nantucket Sound, and from these data NHESP developed the spatial representation of their core habitat. The core habitat represented in the planning area includes night-time concentration areas north of Nantucket and the area of concentrated commutes to the south of Nantucket. Long-tailed Ducks have a unique winter behavior where they make a daily "commute" from Nantucket Sound, where they concentrate in particular areas at night, across Nantucket Island to Nantucket Shoals, where they disperse to feed during the day. Because this behavior and Long-tailed Duck spatial distribution on Nantucket Shoals is being studied, the plan does not indicate core habitat for long-tail ducks south of the planning area.
To allow for consistent evaluation and comparison of a variety of datasets with distinct spatial resolutions, accuracies, and other characteristics, the Massachusetts ocean management planning area was partitioned into 250 x 250-meter grid cells, each with a unique ID. These data were converted to the planning area grid by extracting all of the cells in which the data layer occurred.