Tuesday, April 16, 2013

Tundra Swans versus Trumpeter Swans

        It's swan season and when birders get together, the subject of how to identify swans seems to be coming up quite a bit. So what is it with these Tundra and Trumpeter Swans? They are both big white birds with black bills. Their names even sound alike, adding to the confusion. They can turn up separately or together almost anywhere. I had a flock of 60 Tundra Swans fly over my house once, for Pete's sake. If they call, that is very helpful in separating them, but what do you do when you have a bunch of swans standing silently in a corn field? I have been lucky enough to run into quite a few swans recently in these very circumstances, and I have a couple of photos that might help people start to sort them out.The idea here is to learn to separate them in less than ideal conditions - the way we usually see them. So even though a yellow loral spot (in front of the eye) or a pink lip stripe are diagnostic field marks, often times these are not useful in the field.
The Famous Trumpeter Swans of Wolf Lake State Fish Hatchery
        The Trumpeter is the one with the pink lip stripe, if  you get a lucky look in good light. But we can't see that in this photo. The area we want to focus on is around the eye. In these two birds, you can't really see the eye. Notice also the angle formed by the back edge of the bill between the eye and the "chin."  Now compare these areas with the same ones in the swan in the next picture.

Tundra Swans, Somewhere in Van Buren County, Spring 2013
        On the Tundra Swan, the eye is distinct from the bill. Part of this is because of the structure of the bill, and part is an optical illusion caused by the yellow loral spot, in front of the eye. Most Tundra Swans have this spot, although it can vary in size and be hard to see in some birds. Also, to me, the Tundra Swan's head is more gooselike, the bill appearing shorter than the Trumpeter Swan. The Trumpeter's bill appears longer and more elegant. Look at the angle we were mentioning before. The back edge in the Tundra Swan appears more vertical, versus more angled in the Trumpeter Swan.
         If you get a great look and can see the yellow spot, or the pink lip mark, or hear them call, by all means, make the most of these clues. But if the swans aren't making it easy on you, I hope you find these tips helpful.
        Questions, comments or suggestions are welcome! Bird on!

Michigan's "Easy" Swan - the aggressive Mute Swan


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