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Cassin's Auklet Identification

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The Four Keys to ID

  • Size & Shape

    A small but rotund seabird with rounded head, very short neck, short, stubby wings, short but heavy bill, and very short tail.

    Relative Size

    Larger than a Red Phalarope, smaller than a Rhinoceros Auklet.

    Relative Sizerobin sizedrobin-sized

    • Both Sexes
      • Length: 9.1 in (23 cm)
      • Weight: 5.3-7.0 oz (150-200 g)

Regional Differences

Two very similar subspecies of Cassin’s Auklet differ mostly in size: the larger aleuticus nests from Alaska to California (and apparently south into Mexico), and the smaller australis nests only in western Mexico, on islands of the Baja California Peninsula.