martes, 27 de octubre de 2015

Blue-winged Teal 2

 Three brown ducks, from left to right: Blue-winged Teal (Anas discors), Northern Pintail (Anas acuta) and Eurasian Teal (Anas crecca)

The female Blue-winged Teal (Anas discors), first seen on Oct 24, was found at a different irrigation pond in Las Martelas (Los Llanos de Aridane) this morning, accompanied by an eclipse male Northern Pintail (Anas acuta) and a female Eurasian Teal (Anas crecca). The conditions for photography at this new location were better than on the previous occasion.

 Female Blue-winged Teal (Anas discors)

Blue-winged Teal (Anas discors)

The suspicion that the previously-mentioned Eurasian Teal (Anas crecca) might in fact be a Green-winged Teal (Anas carolinensis) has naturally crossed my mind. The females of both species can apparently be separated in the field but so far, I have been unable to appreciate the subtle differentiating features.

Circumstantial evidence includes the fact that both the Blue-winged Teal and the other possible American species appeared on the island roughly at the same time, and seem to have formed a partnership bond over the last few days, foraging, roosting and moving from pond to pond together. Another persuasive argument in favour of Anas carolinensis is the fact that Eurasian Teals (A. crecca) tend to reach La Palma in small flocks, rather than as solitary birds.

Further observations are required.

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