Saturday 24 October 2020

[cobirds] Lagerman Swans Update

All:

Just got a very nice email from Christian N. who reviewed my (possible) Trumpeter Swan listing from this morning.  Short version I changed it to Swan sp. as a 100% ID is not possible. 

(Heads up this is a lengthy post, but I think of some you will learn something new, I sure did.)

Christian had some great tips on Tundra vs Trumpeter, as well as two other buckets of info that I think most of us would have no knowledge of:  one was what he sees as a reviewer (he sees lots of false alarms, like mine), as well as some state or geographical knowledge that I would imagine a lot of birders are unaware of.

Here's his ID tips:
The ID of long-distance swans is rather tricky, so I'm reticent to accept a report of Trumpeter without some solid photos that show multiple angles of the bill. I find the side profile to be relatively unreliable, with the forehead feather shape being more conclusive at long distance. But, that's only good on adults. The lack of yellow gets most people, but in reality the yellow is usually just very small so hard to see at a great distance.

Geography tip:
Trumpeter Swans are well established along the major rivers in western CO (you referred to some in Mesa Co.). They are very much expected there. Not so much along the Front Range, where there might be one or two bonafide records each winter. I don't know anything about the Rawhide birds, but I would bet they are mis-IDed Tundras.

Reviewer "insider" things he sees:
I hate to be a skeptic, but I don't think that Tundra can be ruled out by your description. They are the much more likely option, and this is when they are expected to move through. The situation where swans are called Trumpeter off the bat only to be IDed later as Tundras repeats itself like clockwork every fall. Almost every single swan that shows up is called a Trumpeter and then it invariably turns out that they are Tundras. This happened with the long-staying bird at Valmont (several years in a row), it's happened with a bird just a few meters from the road near Hygiene a few years ago (found and mis-IDed by one of the "local hotshots"), it happened when a group of 9 showed up at Sombrero Marsh (again, birds were spitting distance from observers and they still called them Trumpeters when they were Tundras), happened last fall when a co-worker found a lone Tundra on a local pond ("I swear, the thing was huge, had to be a Trumpeter"). And on an on.

So, I took a swing and missed it (pro tip:  don't leave your camera at home).  I learned some ID tips, some geography tips (go see them on the western slope), and I'm not the first one to mis-ID these two species.

Happy Birding

Jay Hutchins
Longmont, CO

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