Sunday, November 1, 2009

Eurasian Wigeon: Redux

Text and photographs (both copyrighted) by Tony Leukering

Things are not always what they seem.

Yesterday (31 Oct), while driving north on Lighthouse Avenue from the State Park, I noted the presence of a lot of wigeon on Lighthouse Pond, enough, certainly, to hide a Eurasian Wigeon. So, I stopped to scan through the bird with my binocular. Michael O'Brien, who had left the State Park immediately after me, passed on by for home. Shortly after he got home (some two minutes later), I was calling him to ask him to come check out a female wigeon that I thought was a good candidate for a female Eurasian Wigeon. He kindly came back and provided the opinion that it was just a slightly-odd American Wigeon. So, I started scanning the rest of the flock that I hadn't checked after finding the candidate and almost immediately found an obvious Eurasian Wigeon, though not an adult male. As the bird was almost right in front of the blind on Lighthouse Pond (accessible from inside the Park), we headed back to the park to get closer and try for photos.

I was the first one to the blind and I quickly found a ruddy-headed wigeon that I assumed was the bird that we'd seen from the other side of the pond. I took a few pictures of it at some distance, all the while nigggling thoughts in my head tried to tell me that the bird looked a bit different, particularly looking not as rusty as the bird that we'd seen from across the way. Of course, I was looking at it under different lighting conditions, so over-ruled my brain's right half (or did I over-rule the logical left half?) and decided that it was the same bird. I then lost the thing while waiting for other birders to show up. Right before others arrived, I found the bird again and it looked just as rusty. Enjoyment was had by all and I left happy. Oh, yeah, we also thought that it was an immature male Eurasian Wigeon.

This morning, I got a text from Michael saying that he'd seen the bird better -- or, at least, he'd seen more parts, particularly the upperwing coverts -- and thought that the bird was a female. Cameron Cox (who co-wrote an article on female Eurasian Wigeon in Birding in 2005) arrived a bit later and sent a text message that there were two Eurasian Wigeons on the pond, neither an adult male, with the "second" bird being a bit duller than the bright rusty one I'd found yesterday and, he thought, an immature female.

Of course, all that got me down to look at the ducks on Lighthouse Pond again, and I fairly quickly found both Eurasian Wigeons. Unfortunately, they were on the far side of the pond, so not particularly photographable. I ogled them for a bit and then concentrated on trying to get interesting pictures of the other species of ducks on the pond, despite the horribly overcast skies (the cold front never did clear today, and we had threatening and more-than-threatening rain all day).

However, once I'd seen both birds, my brain (left, I assume) started working on my sightings yesterday. The first thing that I did upon getting home from birding was check my distant pictures of Eurasian Wigeon from yesterday to compare to the much better pictures that I obtained of the "rustier" bird that was close to the blind. When will I listen to that right brain of mine?

(Click on image to see a larger version.)

Comparing the two images -- the duller (distant) bird on the left and the rustier (close) bird on the right -- there is a number of differences between the two birds, but the most obvious one is the scapular patterns of the two birds. The duller bird has thinner and less reddish fringes to the scapulars with the leading edges being particularly narrow and, in some, whitish. The rustier bird, however, has wide and very rusty fringes to all scapulars. Additionally, some of those feathers, particularly the lower scaps, also sport small pale spots in their centers that the duller bird completely lacks.

So, there is still some discussion about the sex of the rustier bird (Cameron holds for an immature male, while Michael votes for female). If the rusty bird is here for the winter, we will be able to solve this one, as, if it's a male, it should molt into basic plumage soon and it will be most obvious at that point.

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