First out of the water, at the top of the image, is a recently-discovered Ring-necked Duck (Aythya collaris), which had been resting in one of the irrigation ponds in Las Martelas (Los Llanos de Aridane), together with 12 Tufted Ducks (Aythya fuligula). Even in this action shot of the birds taking flight, the two species can be easily differentiated...
Ring-necked Duck (Aythya collaris) with 5 of a flock of 12 Tufted Ducks (Aythya fuligula)
"The Ring-necked Duck, a Neartic equivalent of our familiar Tufted Duck, is distributed in the breeding season throughout a large part of North America, from Alaska and British Colombia to Newfoundland and New England. In the mid-1970s there was an estimated population of half a million, but numbers have greatly increased since then, as the bird's range has extended eastwards. The species winters along the coasts of the United States, mainly in Florida, and also in the West Indies, Mexico and Guatemala. Vagrants occasionally reach Venezuela and Trinidad, as well as Japan, Hawai and, of course, the Western Palearctic.
The first record in mainland Spain was a male seen in Gijón (Asturias) in 1978, and the first on the Canary Islands was a female found dead in San Sebastián de La Gomera in 1981. Since 1989-1990 the species has been observed regularly every winter, and so far there are 65 officially accepted records in Spain, 29 of which are from the Canaries. The vast majority of sightings occur between November and March. The species was removed from the British Rarities List in 1993, after 335 records had been logged." (Information adapted from Aves Raras en España, de Juana, E., Lynx 2006)
According to the same book, the last sighting of this species on La Palma was a female observed between February and March 2000, with a previous record from Santa Cruz in 1981, also a female.
Ringed-neck Duck (Aythya collaris) and Tufted Duck (Aythya fuligula) for comparison
In the above photo, the duck's large head with its distinctive shape, the pale eye ring, the whitish, sub-terminal band on the bill, and the short, pale horizontal line behind the eye can all be appreciated, together with other plumage details of what I take to be a female.
This sighting will be submitted to the Spanish Rarities Committee in due course.