Fork-tailed Storm-Petrel Identification

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The Four Keys to ID

  • Size & Shape

    A small, sturdy seabird, heavyset for a storm-petrel. Has long, pointed wings and a long, forked tail. The neck is short and the bill fairly small. The feet do not extend past the tail in flight.

    Relative Size

    Slightly larger than a Leach's Storm-Petrel, smaller than a Buller's Shearwater.

    Relative Sizebetween robin and crowbetween robin and crow
    Measurements
    • Both Sexes
      • Length: 7.9 in (20 cm)
      • Weight: 1.8-2.8 oz (50-80 g)

Regional Differences

The more northerly populations (subspecies furcata), found from northeastern Asia to Alaska, are larger and paler than those that nest from southeastern Alaska southward (subspecies plumbea). However, these differences appear to be clinal—that is, there are intermediate birds where these populations meet. Northern birds tend to feed closer to shore, often alone, while southern nesters often feed farther from shore, frequently in small flocks.