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Chapter 12 - Coastal & Marine Birds© Glen Smart/US Fish & WildlifeMaine and Monomoy Island National Wildlife Refuge inMassachusetts for up to three weeks before initiating theirsouthern migration.Roseate Terns are thought to migrate south during Julyand August from the breeding areas along the northeasternUnited States and Canada to the Caribbean and thento Brazil (Kirkham 1988). The winter range is poorly understood,but they have been found in significant numbersnear Bahia, Brazil. In spring, their northern migration islikely oceanic since they are rarely seen from land untilthey arrive in the northeastern United States.Harlequin Duck (Histrionicus histrionicus)Harlequin Ducks breed from Iceland west to easternSiberia (Robertson and Goudie 1999). Within NorthAmerica, there are two distinct breeding populations: aneastern population that breeds from Labrador south toNewfoundland and a western population that breeds fromWyoming north through Alaska and western Canada(Robertson and Goudie 1999). There are no breedingharlequin ducks within the Northwest Atlantic region.However, most of the eastern North American breedingpopulation (thought to be somewhat less than 1,500 individuals)winters in the region along the coasts of NovaScotia and New Brunswick south to New Jersey (Vickery1988, Mittelhauser 2002).Harlequin Ducks build nests along fast-moving white-waterrivers and streams in May and June. Most eggs hatchin late June and July. After breeding, from July throughOctober, the ducks gather in larger groups before migrationto the coast. No harlequin ducks have ever beenobserved migrating, so it is unknown whether they flydirectly from breeding to wintering areas (the most likelyscenario, as they have not been sighted migrating) or stopover at points in between. Harlequins winter along rockycoastlines in shallow marine waters. Birds can be observedon wintering grounds as early as September, but the largestnumbers arrive in October and November.Audubon’s Shearwater (Puffinus lherminieri)There are no breeding Audubon’s Shearwaters within theNorthwest Atlantic region. Within this region, the largestconcentration of this species is found offshore of CapeHatteras, North Carolina in the fall.Audubon’s Shearwaters initiate courtship in lateNovember and begin egg-laying in January-May in theBahamas (approximately 60% of the breeding population),Cayo del Agua, and the Lesser Antilles from the VirginIslands to north of Tobago (Lee 2000). Breeding activityis nocturnal. Most of their nests are found in burrows, oncliffs, or under boulders on rocky open ground.After breeding in spring to early summer in theCaribbean, most Audubon’s Shearwaters follow the GulfStream north off the southeastern coast of the UnitedStates. Approximately 50-75% of the species’ populationcan be found during the summer and early fall in a majorforaging concentration area near Cape Hatteras, NorthCarolina (Lee and Socci 1989). Here they occur “along[the] inner edge of the Gulf Stream or over waters 50 to500 fathoms deep” (Lee 1995). They can be found withinthe Gulf Stream as far north as Massachusetts in latesummer.12-20Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report