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Posted by Toe on 23:08:57 05/27/07
In Reply to: question & more info on "Commic" Tern posted by Elsa
Elsa brings up a good point on the legs. When we first saw the bird it flew from right in front of us to a point farther down on the boardwalk. Upon seeing the small bill, the very short legs, and the short neck, my first thought was Arctic Tern. We spent a good 30 minutes observing the bird and taking photos. The scope was very helpful in showing more detail and allowing the photos. We both determined what Bill Pranty has pointed out: that this is a first summer bird. With that in mind, and after several hours of studying the books and photos online, here's why I an now somewhat sure it's an Arctic Tern:
1) The very short legs almost rule out Common Tern. At no point, no matter how the bird stood, did the legs look any longer than in the photos. Also, the color of the legs (deep red) is more consistent with Arctic than with Common.
2) The bill looks quite consistent with the photos of Arctic Terns I've found. Also, the Common Tern achieves an orange-red bill. This bird looks like it's transitioning from an all-black bill to a dark red bill. This dark red is more consistent with Arctic than with Common.
3) The head seems awefully short to me. This is one field mark I noticed quickly. I've seen plenty of Common Terns and they looked "normal" headed like in any other tern, but this bird just has a funny look to it. The short head/neck was very obvious when the bird flew. Hard to explain, but you had to be there.
4) The faint carpal bar (according to both National Geographic and Sibley's) is consistent with Arctic Tern, expecially for a 1st summer bird. The carpal bar is much more pronounced in Common Tern. Elsa and I knew the bird would fly when we saw 3 people walking on the boardwalk. We both made an effort to watch the wings when it flew and we saw no distinct carpal bar on the leading edge of the wings as you would expect on a Common tern, and..
5) The primaries did not have the dark edge you'd expect on a Common Tern. We saw even gray primaries on the bird when it flew, quite lightly in color in fact.
6) The only field mark pointing more towards Common than Arctic is the tail. but our first impression was that this bird had tail feathers missing. The tail doesn't look right for either species, and in the photos you can see that the right streamers are shorter than the left. In person, the feathers looked really worn. I'm not sure if this is due to a molt or just wear and tear due to weather. It's more than likey normal molt, since the bird is obviously transitioning as can be seen by the bill.
So, there's my trivial input, but it's based on a lot of input from a lot of sources and taken very seriously. If I've really missed something, please feel free to point it out. I'm am the first to admit that I don't have all the answers, and every mistake is a learning experience. I hope someone else can see it in person and make a determination that way. It's still a beer bird either way, so I'm happy.
Cheers!
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