- Cassin's Auklet Ptychoramphus aleuticus. Two subspecies in the northwest Pacific:
- P.a. aleuticus. Channel Is. of California to Aleutian Is.
- P.a. australe. Breeding Baja California.
Cassin's Auklet Ptychoramphus aleuticus aleuticus Newport, Or., USA
Culmen: 16.5 mm; total: 52.8 mm, unsexed adult
A monotypic genus. The Parakeet Auklet has a very conspicuous bright orange-red colored bill. It is of the same size as the Crested Auklet, but has no crest.
- Parakeet Auklet Cyclorrhynchus psittacula, from Alaska to northeast Asian coast, dispersing in North Pacific.
Two species of this genus are the smallest among al alcids. The Least Auklet hardly bigger than a sparrow. All of them having orange bills in their adult stage. The Crested Auklet molts a part of its ramphotecal coating, like the puffins and has a smaller orange bill during winter.
- Crested Auklet Aethia cristatella, northern Pacific form Alaska to northern Japan.
- Least AukletAethia pusilla, northern Pacific to Bering Strait area.
- Whiskered Auklet Aethia pygmaea, northern Pacific, north-east Asia and Aleutians.
Crested Auklet Aethia cristatella Chukotka, Sachalin, Russia
Culmen: 13.2 mm; total: 54.0 mm, unsexed adult