Black-tailed Godwit (Limosa limosa)
At the end of January, I observed the plainer of these two birds in an irrigation pond in Las Martelas (Los Llanos de Aridane). Presumably, this is a non-breeding adult, probably a female due to its larger size and longer bill. I was unable to get decent photos on that occasion, so didn't bother to post the sighting, and, as there are very few ponds available for waders at present (water levels are generally too high), I assumed the bird would fly on rapidly.
Black-tailed Godwit (Limosa limosa) - male acquiring breeding plumage
However, on returning to the area on Feb 7, I was surprised to find not only the first bird still there, but also a second individual, presumably a male moulting into breeding plumage. The following images allow size comparison, differences in bill colour and length, and other plumage details to be appreciated.
Although both birds have relatively steep foreheads as in islandica, on the basis of distribution, the most likely race would appear to be the nominate limosa. According to "Shorebirds of the Northern Hemisphere" (Richard Chandler), islandica only winters as far south as Morocco (where it overlaps with the nominate race), while limosa reaches sub-Saharan Africa. Comments would be appreciated.
Just to discount the remote possibility of haemastica (Hudsonian Godwit), the image below shows the white - not black! - underwing coverts.
Black-tailed Godwits have been recorded previously on La Palma, and are classed as regular winter visitors and passage migrants to the Canaries (all islands), but this was my first sighting of the species on the island.
Incidentally, the female Ring-necked Duck (Aythya collaris) featured in a previous post, was still in Las Martelas on Feb 7, together with 13 Tufted Ducks (Aythya fuligula). A male Ring-necked Duck was also reported by a visiting birder in January, at the Laguna de Barlovento.