American Golden Plover (Pluvialis dominica)
As reported in the blog of the Canary Island SEO Delegation (see: avescanarias.blogspot.com), an American Golden Plover (Pluvialis dominica) was discovered in Las Martelas on September 10th, in a basin very close to where a juvenile of the same species appeared in October 2009. The present specimen, however, is clearly an adult in the process of moulting from breeding to winter plumage.
In the image above, the long primary projection beyond the tertials can be appreciated, typical of the American (dominica), rather than the Pacific (fulva) Golden Plover.
The buff-greyish axillaries shown below allow both the European Golden Plover (P. apricaria) and the Grey Plover (P. squatarola) to be discounted:
Despite persistent attempts to get as close as possible in good light conditions, the following images are the best I have obtained of the bird's critical tail area: according to the literature there should be at least 4 primaries projecting beyond the tertials, two of which should also project beyond the tail. Unfortunately, none of the photographs allow this characteristic arrangement to be distinguished.
Depending on the state of the bird's moult, such fine details may, apparently, be partially concealed or difficult to appreciate, but, judging from the raised-wing shot above, none of the primary feathers seem to be missing.
Still on the island at the time of writing, this rare North American migrant may well resume its journey in the next few days.
All in all, an interesting sighting which will eventually be submitted to the Spanish Rarities Committee for expert appraisal.