Cassin's Auklet

Ptychoramphus aleuticus




Auks, Murres and Puffins (Alcidae)

Code 4


Code 6



Egg Color:

Creamy white, tinted blue or green, nest stained.

Number of Eggs:


Incubation Days:

37 - 42

Egg Incubator:

Both sexes

Nest Location:

In burrow or on rocks.

Nest Material:

No nest materials.


Northern birds migrate



Cassin's Auklet: Small seabird with slate-gray upperparts, pale gray underparts, and white belly. Eyes are pale yellow. Bill is short with white at base of lower mandible. Tail is short. Sexes are similar. Juvenile has dark brown eyes.

Range and Habitat

Cassin's Auklet: Breeds from the Aleutians down the Pacific Coast of North American to central Baja California. Winters in waters off the southern part of breeding range from southern British Columbia south. Pelagic, with preferred habitats consisting of open ocean; nests on sea cliffs and isolated headlands.

Breeding and Nesting

Cassin's Auklet: One white egg, blue or green tinted, is laid in a burrow or cavity among rocks. Incubation ranges from 37 to 42 days and is carried out by both parents.

Foraging and Feeding

Cassin's Auklet: Feeds on small crustaceans and fish. Forages by chasing prey underwater, propelled by its wings. They can dive more than 120 feet below the surface.


Cassin's Auklet: Gives weak croaking calls at night.

Similar Species

Cassin's Auklet: Tufted Puffins and Rhinoceros Auklets are larger with heavier bills.


Belly, undertail coverts, chest, flanks, and foreneck.

Back, rump, hindneck, wings, and crown.
The ventral part of the bird, or the area between the flanks on each side and the crissum and breast. Flight muscles are located between the belly and the breast.
Lower mandibleX
The lower part of the bill.
The pelagic is a type of bird whose habitat is on the open ocean rather than in a coastal region or on inland bodies of water (lakes, rivers). An example of a pelagic bird is the blacklegged kittiwake.
Parts of a Standing bird X
Head Feathers and Markings X
Parts of a Flying bird X