9/12/2009

Telling One Good Tern From Another

banded tern copy
I think it is very difficult to ID shorebirds.  Many shorebirds species look almost identical, with only minute variations in size or coloring. In many species, appearance changes dramatically as they age, and some species even look different during different months of the year! The tern species we see around here are very confusing.  There were two species of terns at South Beach the day we went: Common Terns and Roseate Terns. During spring and summer, adult Roseate Terns can usually be identified by their thin black bills (as opposed to the orange and black bills of Common Terns). But not always.

banded tern 2
This bird's bill looks very black, but since it is immature, a black beak is meaningless. Both species have dark bills when immature or non-breeding. Mature birds have solid black caps, but this bird has a white forehead. This bird has been banded, but that is no help to me.

banded tern face front copy
The white forehead looks rather un-ternlike, but virtually all terns have a white topped head more often than not.

ternocean
The dark band on the shoulders is something I associate with Common Terns, but . . .

TW tern copy
this is also a juvenile bird, so who knows?

southbeach tern
The best bet is to say they're all Common Terns, and let it go at that!

3 comments:

  1. At Hilton Head, SC this summer I saw line after line of Common Terns...and Iove them! Great photos...

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  2. Thank you, Kelly. We went back to South Beach and saw some Black Terns! If I didn't have pictures, I wouldn't believe myself!

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  3. You seem to know a lot about terns. I have recently moved to the Texas coast and have just begun to learn about shore birds. I am trying to identify a bird that by size, stance, hovering and diving looks like a tern, but has a totally black head and long black beak. The black head is crowned with a black raggedly tuffted head. A white ring separates the head from the black back and greyish breast. I have looked at pictures of terns on line. The closest I have found is the sandwich tern, but it doesn't have the all black head and beak. Can you point me in the right direction?

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