Wednesday, March 7, 2012

Splits, Past and Future

After traveling a great distance, the first thing we want to do is jump off the plane and go in immediate search for all of the local specialties. This was especially so when we flew to the Seychelles islands in 2009, where, being half-way around the world I expected that every single bird we saw would be brand-spanking-new. And this was very nearly so, with very few exceptions. But after landing in our tropical paradise, imagine the anticlimax when one of the first birds we spotted from the car on our ride from the airport was a Common Moorhen. Hadn't we just come all the way from Florida, where we could reliably find at least one simply by opening the front door?!

Common Moorhen. Look familiar?

Now, two-and-a-half years later, I regret not paying those Moorhens closer attention. With the AOU's announcement of a split last year, that Moorhen that I had so disdained represents a life bird! It's better than I deserve, certainly, although I like to think that I've learned my lesson. Never again will I forget to admire the seemingly commonplace, amongst all of the dazzlingly new -- who knows what the future holds? 

This lucky bird gets to keep his name
Common Moorhen. Don't let the name fool you -- this bird is an impostor

In hindsight, the differences between that bird (Common Moorhen) and our birds (henceforth, the Common Gallinule) are slight, but noticeable (not that they would ever have been apparent without this handy illustration by David Sibley). As you can see, the top of the shield is more rounded in the Eurasian counterpart than in his American cousin. It also has slightly more yellow on the lower mandible.

Interestingly, the local Seychelles population (Gallinula chloropus seychellarum) may even be separable from mainland populations, at least in the hand. There was a time, before the land predators came, that the Moorhen began evolving in the direction of flightlessness. As a result, their wings are considerably smaller than in the nominate subspecies (161 mm vs. 180 mm).

Close-up of a Common Moorhen. Notice the shape of the shield, and the amount of yellow on the lower mandible

Close-up of a Common Gallinule for comparison. This is the one you know and love

One additional sighting could be cause for future celebration. It seems that just about everybody expects that sometime soon, the AOU will split Whimbrel into two species: Hudsonian Whimbrel and Eurasian Whimbrel. If/When this happens, our Seychelles trip will have yielded a further armchair tick. The difference from the above split, though, is that we were genuinely excited to see Whimbrels in Seychelles, because they were our first. 

'Eurasian' Whimbrels - Someday I may get to take the quote marks out
  
'Eurasian' Whimbrels

We would later see a Whimbrel at Ft. DeSoto in Florida, but only one, and from farther away. So, strangely enough, we're better acquainted now with the 'Eurasian' than the 'Hudsonian' variety, despite the latter wintering nearby. It's a strange state of affairs, but I'll take what I can get. 

'Eurasian' Whimbrels

While we were traveling, the possibility of future splits was the furthest thing from my mind, even while I relished the progress my life list was making. It all just goes to show that you should never take anything for granted, and that no difference is too slight to try to notice and record. In the long-run, those superficial-seeming differences might prove to be much deeper than they seem.


Reference:
Skerritt, A., & Bullock, I. (2001). Birds of the Seychelles. Princeton, NJ: Princeton University Press.

4 comments:

  1. I'd hoped the Moorhens would work it out, but I guess the divorce was inevitable for some time now. Tisk Tisk, I'm now 1 bird farther away from seeing every bird in the world. :: :Sigh: :: I guess one Moor can't hurt.

    I love the Whimbrels there storming the beach a la Normandy 1944, looking for Germans whose brains they can eat with those decurved beaks (that IS what's going on in the picture right)?).

    Really enjoying these Seychelles posts and the tropical feel they bring, thanks for sharing.

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    1. Mo' birds, mo' problems. Another bird to track down sounds like the right kind of problem to have, though... unless the man-eating Whimbrels have anything to say about it.

      Glad you're digging the Seychelles posts - there are lots more on the way!

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  2. The Old World Whimbrel would also be an armchair lifer for me...I spent a lot of time scouring the shorebirds of Midway Atoll and this was one of the few unusual migrants I could find...fortunately, it was in a flock of Bristle-thighed Curlews, which made for a nice comparison.

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    1. Armchair ticks are pretty sweet. I think I'll have to get out my armchair if I expect to list any Bristle-thighed Curlews, though. Or maybe just find myself a nice armchair on Midway Atoll

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