Abstract
We conducted 38 aerial surveys of seabirds south of the islands of Nantucket and Martha’s Vineyard, Massachusetts between 22 November 2011 and 14 January 2015. The study area, which extends approximately 85 kilometer (km) offshore to the 60 meter (m) depth contour, has been designated as a “Wind Energy Area” (WEA) by the Federal Bureau of Ocean Energy Management (BOEM lease blocks in Figure 1). We sampled approximately 23,000 linear km of transect over the three years. We mapped the distribution of all birds from data sampled along standardized strip transects. One of our goals was to detect the presence of persistent “Hotspots” of seabird activity; that is, locations where larger than average aggregations of seabirds occurred on a regular or repeated basis. We identified two Hotspots of seabird abundance: one near the western edge of the Nantucket Shoals, consisting mainly of Long-tailed Ducks and White-winged Scoters during winter, and Common and Roseate Terns during spring, and a second one in the Muskeget Channel area, consisting of scoters and eiders, loons, and terns. Overall densities of seabirds in the area were similar between years (Kruskal-Wallis ANOVA, p > 0.1).