Sunday, May 9, 2010

Wandering Tattler

Yesterday I set out for Los Cóbanos, a small community on the (Pacific) coast of western El Salvador, in hopes of encountering 'rock-pipers', a collective name for western shorebirds found on rocky shorelines. Some species in this group don't winter in Central America, so down here, looking for rock-pipers really means looking for Surfbird and Wandering Tattler. I also hoped to see a Red-billed Tropicbird - not a shorebird but a bird associated with similar habitat.

I knew Surfbird would be harder to find, but, as my friend Oliver Komar said, I'd have a good chance of finding some Wandering Tattlers. And indeed I struck out on Surfbird, but I did find a couple of Wandering Tattlers.

Wandering Tattler is a shorebird that breeds in Alaska, the Yukon and northwestern British Columbia, and winters throughout all but the southernmost portions of the Pacific Basin. It's not a common species, with current population estimates ranging from 10,000 - 25,000 (Gill et al. 2002). In spring, migrants move north from March through early June, while most subadults (i.e. those 10 - 34 months of age) remain on the non-breeding grounds through second and likely third boreal summers (Gill et al. 2002). Second and subsequent prealternate molts (i.e. into breeding plumage) take place on the wintering grounds from February onwards and are completed in May (Gill et al. 2002).

Both of the birds I observed were in basic, or non-breeding plumage, and likely subadults.

In alternate (breeding) plumage, this bird has heavily barred underparts. Basic-plumaged birds have whitish underparts. Note that the bird I photographed has a few dark feathers on the white belly and lower breast: an older subadult perhaps?

Walking around, this bird sometimes 'bobs' in the manner of a Spotted Sandpiper, although - from what I observed on yesterday's individuals - certainly not as frequently as that species.

I also found this Whimbrel, a bird that winters here. An influx of northbound migrants from points further south is noted in Central America from mid-March to early May (Skeel & Mallory 1996).

Incidentally, I did see a Red-billed Tropicbird, but I didn't get very satisfying looks, or indeed any photos. This was a 'life bird' for me, and exciting as it was to add a lifer, the excitement was tinged with a bit of disappointment, for the bird did not come close. It wasn't far out over the ocean; in fact I saw it flying over some scattered rocks near shore where I had birded some 30 minutes earlier. Immediately obvious was its odd way of flying, with rather fast wing beats that did not seem to propel the bird at a concomitant speed; I could also make out dark outer primaries. Beyond that, I was not able to see very much detail on this bird, and I hoped to see it or a conspecific at closer range. Despite some time spent searching air space over the water, this did not happen. I did see some Franklin's and Laughing Gulls, and many Black Terns, as well as several Royal Terns. I had hoped to see some Blue-footed or perhaps Nazca Boobies as well, but didn't see any sulids.

Literature cited:
Gill, Robert E., Brian J. Mccaffery and Pavel S. Tomkovich. 2002. Wandering Tattler (Tringa incana), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:
Skeel, Margaret A. and Elizabeth P. Mallory. 1996. Whimbrel (Numenius phaeopus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:

No comments: