A blog mainly about birds and birding, to supplement my website I shall add new posts on an ad hoc basis as and when I have something I think is worth sharing, whether that’s an interesting bird, something I’ve learned, perhaps about identification, or something that’s aroused my curiosity. Often there will be questions, some of which you might be able to answer... please use the comments!

Monday, 4 June 2012

Confusing Yellow Wagtails - part 2

One enjoyable moment hunting for migrants in Sicily was finding a mixed flock of 10 flava Wagtails in a dried out pool at Capo Murro di Porco.  It contained Blue-headed Wagtails, Grey-headed Wagtails, a Black-headed Wagtail (nice call) and another curious bird, the point of this post.

Before I get on to the bird in question, let me wallow in some Grey-headed loveliness:

Grey-headed Wagtail, Capo Murro di Porco, 4th May 2012

I didn't manage to get such a good shot of the Black-headed, but it was such a gorgeous bird I can't resist sharing it:

Black-headed Wagtail, Capo Murro di Porco, 4th May 2012

And now, the bird I'm really writing about.  This was a really striking bird!  A lovely dark slaty-grey head, really dark at the front (fore-crown, lores and front of ear-coverts) but paler, almost bluey grey at the rear.  A vivid white supercilium and white lower eye-crescent, but no white in the middle of the ear-coverts.  The throat was clearly yellow but the chin was white, with white extending slightly down the moustaches.  Here it is:

flava Wagtail, Capo Murro di Porco, 4th May

So what is it?  Yellow throat should rule out the cinereocapilla/iberiae complex  I thought it might be a Romanian 'dombrowski'-type intergrade?  What do you think?

Confusing Yellow Wagtails - part 1

I was hoping to score some nice Ashy-headed Wagtails in Sicily, and so I did.  Only at one site I visited though - the wetlands at Granelli.  Only managed to get one distant shot of a 'textbook' Ashy-headed though:

Ashy-headed Wagtail, Granelli, 1st May 2012

One bird was much closer, and as it was singing its heart out and clearly holding territory it should have been Ashy-headed... but what about that supercilium?

flava Wagtail holding territory, Granelli, 3rd May 2012

Now, is it me, or does this look rather like a Spanish Wagtail iberiae?  Are there Spanish Wagtails breeding in Sicily?  I saw iberiae in Portugal a few years ago and I think most of them had a narrower supercilium in front of the eye, but variable.  Or is it an intergrade/hybrid (with Blue-headed?)?  Or can Ashy-headed Wagtail look like this?  What would you think it was if you saw it in England?

Here's another.  This one was in the same area and looked more like Blue-headed, showing both a pale supercilium and pale in the middle of the ear-coverts.  But the tone of grey on the head - that didn't look like Blue-headed.

flava Wagtail, Granelli, 28th April 2012

Both of these birds have some green on the sides of the crown.  What does that indicate?  I've seen it on Blue-headed Wagtails previously but never quite figured out if it's an age-related thing or something else.  I wouldn't have any trouble seeing the second bird above as a first-summer - when I first glimpsed it I thought it was a female.  But the strikingly colourful first bird - can that be immature?

So help me out - what are we dealing with here?

Ferruginous Ducks

A female Ferruginous Duck turned up in the Norfolk Broads a couple of years ago.  Eventually news of its presence reached the news services and lots of people went to see it.  Most of them were happy with the ID but one or two of the locals who'd originally found it and watched it for prolonged periods felt that it wasn't quite right - and was therefore a hybrid.  Last winter it returned, this time accompanied by what was certainly a hybrid, but the identity of the original bird was still doubted by some people.  I've heard three reasons cited why this bird may have been a hybrid:
  1. The head shape was wrong, looking too rounded for much of the time and lacking the peak that is associated with pure Ferruginous Ducks.  My own views confirmed that this was the case - although on occasion it could look quite peaked, most of the time it looked very round.  But was this really wrong for females?  Certainly a male looking like this would and should arouse suspicion, but I wasn't quite convinced it was wrong for a female.  However I wasn't experienced enough with females to be sure.
  2. The bill shape was considered not quite right.  Personally I thought it looked ok: although at some angles it sometimes looked a bit dubious I couldn't see anything hugely concerning in the bill shape.
  3. The white on the belly had been observed to be too indistinctly-bordered for a pure Ferruginous Duck.  I got a couple of brief views of its belly and to be honest I didn't think it was too indistinct.  Sure it wasn't as neat and tidy as it can be on a male, but it wasn't bad.
Personally I suspected it was the genuine thing, a pure Ferruginous Duck.  But although I've seen a few Ferruginous Ducks they've all be in the UK where any record is tainted with the possibility that it's escaped from a collection and may not be pure.  Also most of the birds I've seen have been males.  I simply wasn't experienced enough with wild female Ferruginous Ducks to be able to make a watertight case for it being a pure bird.  It certainly wasn't a first-generation hybrid but a hybrid backcrossed with Ferruginous Duck would be feasible in captivity and some people felt this was the most likely ID.

Ferruginous Duck, Cockshoot Broad, 12th November 2011

In Sicily I got the opportunity to study a number of Ferruginous Ducks in the wild that were free from the curse of uncertain provenance and were unlikely to be hybrids (at least not all of them!).  I learnt the following:

  1. The rounded head shape shown by the Norfolk Broads bird was perfectly normal for female Ferruginous Duck.  Just like the Norfolk bird, the females I observed in Sicily changed their head shape according to posture, sometimes looking peaked but most of the time looking rounded.  I could see no difference in head shape between the Norfolk bird and the birds in Sicily. 
  2. The apparent bill shape varied too.  Some birds, some of the time, seemed to have much less impressive bill shapes than the Norfolk bird.  Of course this has more to do with angle to the observer than anything else, but there did seem to be a little variation in the bill shape - some females seemed to have fractionally shorter and more concave bills than expected.
  3. Females seen in flight and rearing up clearly showed variation in the belly pattern.  Some were less well-defined than the Norfolk bird.  One bird was much less so, although I did wonder if the poor definition on that bird wasn't caused by dirt rather than actual plumage pattern.

 Ferruginous Duck, Granelli (Sicily), 1st May 2012

Ferruginous Ducks, Granelli (Sicily), 29th April 2012

I noticed a couple of things about the males too that I've sometimes wondered about when I've observed this on birds in Britain:
  1. The head can look rounded on males too, though with prolonged viewing it always reverted to the classic peaked shape.
  2. The contrast between the breast and the flanks varies according to angle to the light.  The same bird can change from having no discernible contrast whatsoever between the colour of the breast and the colour of the flanks to having such a strong contrast that it made me think for a moment that I must have found a hybrid. I knew this was the case on some of the British birds I've observed but it was reassuring to see that it was also the case on genuine wild birds in Sicily.

Ferruginous Ducks, Granelli (Sicily), 29th April 2012

Lots more photos of Ferruginous Ducks from Norfolk and from Sicily at