Acadia National Park

Description  ALL BIRDS Sooty gray, but can look all-dark at a distance, except for pale panel on upper wing coverts. Note that tail's fork is not always easy to discern and pale gray line that divides rump is visible only at very close range. Underwings are all-dark.

Dimensions  Length: 8-9" (20-23 cm)

Habitat  Oceanic, seldom approaching land except during breeding season at night. Nests in burrows on remote islands off Canadian coast with some sizeable colonies.

Observation Tips  Tricky to observe since it shuns land and typically does not follow boats. Chance encounters from pelagic trips offer the best opportunities.

Range  Eastern Canada, California, Northwest, Southeast, Alaska, Mid-Atlantic, New England, Florida, Western Canada

Voice  Silent at sea, but at breeding colonies birds utter a bizarre-sounding gurgling rattle.

Discussion  Tiny by seabird standards, but with relatively long wings and a deeply forked tail. Flight direction and pattern are ever-changing, often bounding with deep, powerful wingbeats, but occasionally gliding in an almost shearwater-like fashion. Combination of forked tail and white, wedge-shaped rump (divided down middle by gray line) is diagnostic. Sexes are similar.