Acadia National Park

Description  ADULT SUMMER Has mainly black upper wings and back, continuous with black cap and back of neck; forecrown and underparts are white. In flight, note dark center to otherwise white upper tail, dark gray primaries, and white trailing edge to dark upper wing. Legs are short and red and bill is red-based and dark-tipped. ADULT WINTER Similar, but black cap and nape are separated from black back by streaked white hind neck. JUVENILE Similar to winter adult, but with paler gray-buff margins to feathers of otherwise dark elements of upperparts. These are molted gradually through first winter.

Dimensions  Length: 18" (46 cm)

Habitat  Local and generally scarce in southwestern U.S., but common and much more widespread on Gulf coast. Nests on sandy beaches. Extremely vulnerable to changing water levels, but more so to human disturbance, both directly and by the presence of aggressive dogs. Present year-round on Gulf coast and Atlantic coast north to North Carolina; summer breeding range extends north to New England.

Observation Tips  Usually easy to see on suitable coasts in Florida.

Range  Florida, Mid-Atlantic, Texas, California, Southeast, Eastern Canada, New England

Voice  Utters a nasal kwuup call.

Discussion  Extremely distinctive, ternlike waterbird with wonderfully bizarre and laterally flattened diagnostic bill. Lower mandible is appreciably longer than upper one and used in characteristic fashion when fishing: feeds in flight (mostly after dark), skimming low over water, bill open, then snapping at prey that comes into contact with lower mandible as it scythes through the water surface. Tail is slightly forked. Often seen in flocks. Sexes are similar.