Sunday 21 February 2016

White-cheeked Pintail x Chestnut Teal

possible White-cheeked Pintail x Chestnut Teal hybrid, Victoria Park (Surrey, UK), 3rd November 2012 - copyright David Darrell-Lambert
(photo ID: 2700)

The identification of this bird is not easy and so far we have not reached a confident conclusion.  Provisionally I've labelled it as possible White-cheeked Pintail x Chestnut Teal as of all the ideas that have been presented so far this one seems to me to be the best, but we are by no means sure.

The rather long pointed tail with white sides suggests White-cheeked Pintail to me, though there are other species with relatively long tails and other species with white edges to the tail, so this is not a certainty.  The pale cheeks fit with that too, though of course there are many other hybrids that show pale cheeks, so this is not a strong supporting factor.  The brown body plumage suggests to me one of the ducks that lack bright body colours, which again fits White-cheeked Pintail (among other species), but of course we do not know that this bird is fully adult, or if it has completed its post-eclipse moult, or indeed if it is intersex.  So White-cheeked Pintail is a tentative starting point for me, not a conclusion.

If right, then the second parent must have black under the tail and a green head.  Probably a wholly green head as the green looks quite extensive, though hybrids involving Wigeon or Teal have also been suggested.  We have seen Wood Duck x White-cheeked Pintail hybrids recently and these have looked quite different, but one of my first ideas was Mallard x White-cheeked Pintail.  But this idea did not convince me, or others I asked.  Mallard hybrids usually show some hint of the curved central tail feathers, whereas this shows nothing of that.  A Chiloe Wigeon x White-cheeked Pintail hybrid looked very different with, among other things, very different pattern to the tertials and scapulars.

It was Joern who first suggested White-cheeked Pintail x Chestnut Teal, though he has been clear that he is not sure and some things seem wrong for this ID.  But the tertials and scapulars of Chestnut Teal are rather close to this bird, and the pattern of the flanks (if not the colour) could easily lead to a pattern like the one shown by this bird.  And it has a green head and black vent of course, and the bill is not dissimilar either.  But should we not expect to see chestnut colour on the body if Chestnut Teal was involved?  Certainly some of their hybrids show chestnut on the body.  Well, there's a photo of a Cape Teal x Chestnut Teal hybrid in one of the Gillham books (Hybrid Ducks: the 5th contribution towards an inventory, plate 68) and that shows only a hint of chestnut on its breast, not at all on the flanks - so rather like this bird in that respect.  We might have expected to see a redder eye on a Chestnut Teal hybrid, but at least it is not darker than that of White-cheeked Pintail (it's actually quite similar to White-cheeked Pintail's eye colour I think).

We've considered other ideas too, involving Teal, Wigeon and even Black Duck, but for me at this point White-cheeked Pintail x Chestnut Teal is the best fit.  That doesn't mean it's right though, so please get in touch if you can help clear this mystery up!

possible White-cheeked Pintail x Chestnut Teal hybrid (same bird as in photo ID 2700 above), Victoria Park (Surrey, UK), 3rd November 2012 - copyright David Darrell-Lambert
(photo IDs: 2701-2702)

White-cheeked Pintail Anas bahamensis
Chestnut Teal Anas castanea

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