Sunday, September 20, 2009
Fortunately, some are easily identifiable--Ruddy Turnstone comes to mind: not only is it large (always a plus in my books), but it really does behave as its name describes, going along turning over stones, pebbles, whatever it can find.
More challenging for me are, for example, Western and Least Sandpipers. Of course, Least is the smallest sandpiper, but size can be tricky, especially because I usually look at shorebirds through a scope and I really don't have a sense of their actual size.
Then there's foot color: Westerns have black and Leasts have yellow feet; at Avra Valey sewage ponds, they recently both had blue (thanks to algae). Belly color should help too: Westerns have a bright white belly, while Leasts are overall dingier. But sunlight and water reflection can play havoc with my color recognition skills.
So here's how I (try to) distinguish these two species. I ignore color and look more at location and posture--and Gestalt, as one of my readers recently pointed out. Where (at the sewage pond) is the bird? Generally Westerns tend to be in the water, while Leasts are often at the edge. Because they have longer legs and a longer bill, the Westerns can spend more time in deeper water, and often dunk their whole head. The Leasts, in contrast, due to their shorter legs and bill, tend to pick rather than dunk.
The differences in leg length contribute to a difference in posture, too. Westerns are more upright--they have a pointed rear end that gives them an elegant look, while the short legs and bill of Leasts give them an overall dumpy/cuter look.
Sound is fairly reliable, too. Westerns have a fingernail-on-the-chalkboard screech; Least's trill sounds lower to me and seems to rise in pitch: at any rate, it is preferable to Western's screech.
And by the way, that boyfriend? He's now my husband, and we have visited many sewage ponds across the States and even across international borders!
I'm still at the beginning of shorebird identification, but I do have these two species down--I hope.