Dead Bird Quiz: One good tern deserves another

23 09 2010

Clearly you all enjoy tern identification about as much as I do, which is not at all. We only had one taker on this one: Libby Rock offered a guess, writing,

1. Nice tail. Common Tern?

2. Gull-like, but not quite a gull bill…? Another tern maybe?

First of all, thank you, Libby, for your compliments on my tail. I didn’t think anyone noticed. And yes, the first bird was a Common Tern. The Common Tern is often referred to as the “typical” tern; not too big, not too small, fits in your carry-on luggage. The species is quite widespread, found on rivers, lakes and ocean environments during the breeding season and migration in North America. It winters along the South American coast. I would like to share this tid-bit regarding the species, courtesy of the Cornell Lab of Ornithology:

“The incubating adult Common Tern flies off its nest to defecate 5-50 m (16-160 ft) away. It deposits its feces indiscriminately in nearby water or on the territories of other terns.”

Bird A was a Common Tern. Note extensive black in the primaries.

In terms of identification, our Bird A is an adult, and they sport a black cap and an orange-red bill. While the forked tail is generally quite long, it usually does not extend past the wingtips when the bird is resting. This is in contrast to the similar Arctic Tern, which has a tail that usually extends beyond the wingtips. In flight, the best field mark to use is a nearly translucent triangle on the outer wing which is made more prominent by the dark primaries and secondaries that surround it.

Bird B, on the other hand, is not what one might term a “typical” tern. As Libby pointed out, the bird seems somewhat gull-like, and this species, the Caspian Tern, has a heavier body and broader wings than any other North American tern. In fact, it is the Largest Tern in the WORLD!

Bird B was a Caspian Tern. Note the stocky body and heavy bill.

Caspian Terns are generally only seen in the Northeast during their migration. Southern Seanetters may see them during the winter, especially along the Georgia coast and in south Florida. Caspians can be seen all year-round along the coast of the Gulf of Mexico.




2 responses

23 09 2010

Oh, Sarah. EVERYONE thinks you have a nice tail.

25 09 2010

Love the insight on tern defecation–good factoid!

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