Mystery Bird: Caspian Tern, Sterna caspia

tags: Caspian Tern, Sterna caspia, birds, nature, Image of the Day

Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:

Scared yet? This is about the meanest-looking bird I've ever seen, which identifies it immediately as a Caspian Tern.

But what are the features that make this animal look so intimidating? Start at the rear. The back end of this bird is square, the tail short and the wingtips (for a tern) thick and blunt--none of that graceful trailing-off-into-nothingness that the streamer-tailed species show. The body is thick and muscular, the legs stout and reptilian. The massive, cylindrical neck is topped by a huge square head, and the bill is a carrot-colored dagger, with a mean angled notch in the lower mandible.

Plumage and soft-part colors will confirm the identification--but don't turn your back on this one while you're checking the field guide! The upper surface of the primaries (visible on the right wing) is much paler than their blackish undersurfaces (visible on the left wing). The black face mask merges into the heavy black streaking on the crown and forehead, making even this non-breeding bird look dark-capped. And the bill has an extensive dark tip, unique among the large terns.

What about this bird's age? Is it a teenage gang punk, or a hardened adult offender? I see a few scallop-tipped feathers on the lower back, and the tertials appear to have ill-defined dark centers. This Caspian Tern is going into its first winter--and it looks like a survivor to me.

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