WatchList Species Account for Ancient Murrelet (Synthliboramphus antiquus)

Qualifies for the list as a Declining Yellow List Species

Photo: © Ashok Khosla

This colonial-nesting alcid is a member of a genus that rears its young entirely at sea. Coming to the burrow at night, the parents incubate the eggs in shifts as long as 2-6 days, but when the chicks hatch, the parents do not feed them in the burrow and they depart the nest after 1-3 days. The parents and chicks reunite at sea through mutual recognition of calls; thereafter the parents feed the chicks until they are full grown, at least a month after leaving the colony. The birds nest in colonies between 1,000-10,000 pairs, smaller than that of other alcids. They breed on islands in the Aleutians and southeastern Alaska and on coastal islands of British Columbia; they also breed on a few islands off Korea, Japan, and eastern Russia.

The birds spend the winter mostly in continental shelf waters within the breeding range and also south to central California, sometimes in large flocks, as well as in the offshore waters of Japan and Korea and as far south as Taiwan. The bird feeds on small fishes and larger zooplankton. Birds at their colony sites suffer heavy predation by Common Ravens and Bald Eagles, and, in some colonies, by rates and raccoons. The murrelet is also a main prey item for the Peregrine Falcon, forming up to 50% of the falcon’s diet during the breeding season.

The total population of the murrelet is estimated at 1-2 million. Its numbers have been severely diminished by introduced mammals on colony island,s including rats, foxes, and raccoons. Colonies in the Aleutians are present only on islands where foxes do not exist. Rat and raccoon predation are serious problems on some islands, reducing colony sizes to about 10% of that of the past few decades. Oil spills have killed many murrelets, especially in the Sea of Japan. At present there are efforts to cleans islands in British Columbia and Alaska of foxes and rats; with the mammalian predators gone, murrelet numbers recover quickly.