Two subspecies recognized:
S. a. antiquus
S. a. microrhynchos

Also known as Black-throated Murrelet or Gray-headed Murrelet
 

Identification

Study of an Ancient Murrlet (Synthliboramphus antiquus) feeding in a quite inlet in Atka Bay, Andreanof Islands in the Aleutian Chain. Photograph copyright of Angus Wilson©.
 

Where and When

Found in the Northern Pacific with a handful of vagrants to the Atlantic (Massachusetts and Britain).
 

Photographs on the web

Literature