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Cassin's Auklet

ID Info
Cassin's Auklet by Yousif Attia / Macaulay Library
Auks SilhouetteAuks
Cassin's AukletPtychoramphus aleuticus
  • ORDER: Charadriiformes
  • FAMILY: Alcidae

Basic Description

A plump, slaty gray little seabird with a small white mark above the eye, Cassin’s Auklet breeds in colonies on islands throughout the eastern North Pacific. This inconspicuous species is unfamiliar to many birders, although it can be quite numerous a short distance offshore of the West Coast. These birds spend most of their lives at sea and only return to their nesting burrows under cover of darkness, when breeding colonies come alive with the eerie screeching of thousands of individuals.

More ID Info
Range map for Cassin's Auklet
Year-roundBreedingMigrationNonbreeding
Range map provided by Birds of the World
Explore Maps

Find This Bird

Cassin’s Auklets forage mostly offshore and out of sight of land, so it's best to take an organized pelagic birding trip to search for them and other seabirds. Watch for these tiny, round-bodied birds taking flight low off the water, with rapid wingbeats, as your boat approaches. On occasion, they come closer to the coast, where they can be studied with a spotting scope.

Other Names

  • Mérgulo Sombrío (Spanish)
  • Starique de Cassin (French)
  • Cool Facts
    • In some places, Cassin’s Auklets dig burrows for nesting, but they have to watch out for larger auk species that may take over their burrows and displace them, including Rhinoceros Auklets, Tufted Puffins and Pigeon Guillemots.
    • When bringing food back to their chicks, Cassin’s Auklets store it in a specialized throat pouch.
    • Cassin’s Auklets time their breeding to coincide with periods of prey abundance. When oceanic upwellings occur earlier than usual, they court and lay eggs earlier. During El Niño events and other times when prey is scarce, they may delay nesting for several weeks or months.
    • To avoid predators, especially large gulls, the Cassin's Auklet returns to its breeding colony only at night.
    • The oldest recorded Cassin's Auklet was at least 16 years, 2 months old when it was found in California in 1993. It had been banded there in 1978.