Saturday 12 November 2016

A hybrid duck, but which?

The most frequently seen hybrid duck in this area has to be Eurasian x American Wigeon. Sifting through any large gathering of wigeon is likely to turn one up; at least one. It has to be remembered there is a complete range of variation from almost perfect Eurasian to almost perfect American. But there's the rub, there is no 'perfect' and how much normal variability within each taxon might blur the boundaries of where introgression may, or may not, begin? Lots of ducks towards the Eurasian end of the scale must go unnoticed, certainly more than towards the American end. Very close views help but on large bodies of water close views are rarer than hybrids.

On my last visit to Mie I stopped briefly to look through a flock always present on a narrow stretch of river and quickly found two birds. One is an easily recognised Eurasian x American hybrid, slap bang in the middle of the range, and so seemed the other at first glance. However, getting past the fact it basically has the head of an American and the body of a Eurasian, closer inspection shows there is definitely more going on and backcrossing should reduce confusion rather than increase it. Could it be a three-way split? This might not be as far fetched as it sounds, afterall when there are so many Eurasian x American hybrids around sooner or later one is going to pair up with a third party.

Unfortunately the bird in question was directly against the light and consequently I've had to lighten the images significantly to allow any details to be visible. But first, just to provide a little context, I'll start with a couple of shots of the 'standard' hybrid also present.

Both head and body are sending obviously mixed signals, there's no doubt this is a hybrid.

There's enough American in it to allow it to be picked up very quickly, birds closer to the Eurasian end of the scale are easy to miss.

So these are the best shots I could manage of the 'funny' hybrid because of the poor light conditions.

Easy to pass off as a Eurasian x American hybrid at a glance but it clearly isn't that simple. The head shape and long bill don't match either wigeon. Are those barred retained flank feathers possible in wigeon? Maybe but given the other anomalous features I think they are the result of 'additional input'. Then there's that spur on the cheeks; this seems a submerged genetic trait which appears in hybrid ducks from time to time but I don't remember seeing it in wigeon hybrids.

Now it's possible to see a black culmen, the neck really is dark rather than being the result of shadow and the forehead is far less clean than it ought to be.

The light is undoubtedly making things difficult but the comb has all but disappeared here. The black of the culmen doesn't quite reach the base leaving a neat 'V', not that that's a great help to guess parentage. The Second and third images also hint at a pale centre to the rump and uppertail coverts leaving a black horseshoe around the longer uppertail coverts.

Because hybrids can throw up features which may not belong to either parent it's difficult (for me) to work this one out. I'm guessing Gadwall, Northern Pintail or Falcated Duck could plausibly be involved, all three being common winter birds here and some, but not all, of the features might be suggestive of each. I've only seen one F1 Eurasian Wigeon x Falcated Duck hybrid and it was an uncomplicated identification.

Eurasian Wigeon x Falcated Duck hybrid.

So, a three-way split or just wigeon (one or the other) plus something else?


  1. Hey Neil, have you considered a Storm Wigeon?

  2. Hi Jamie, I was quite unaware of the name Storm Wigeon, thanks for introducing it. However after checking your link I'd say Storm looks rather like a super-American, and rather smart, whereas my bird definitely looks sub-American and a bit scruffy;)