Description

A blog mainly about birds and birding, to supplement my website www.gobirding.eu. 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!

Wednesday, 23 December 2015

Intersex Wigeon?

I have seen a number of female Wigeons showing white behind the eye and when I found a first-winter male with white behind the eye at Salthouse in December 2012 I assumed I was seeing the same phenomenon again.  I thought it was coincidence when I saw a similar first-winter male in the same spot in February 2014 but when I heard it was back in late 2015 I realised they all had to be the same bird.  Not only were they all very similar, clearly aberrant, birds but they were in precisely the same spot, away from the main flock of Wigeon that winter at this site.  They have to be the same bird, and if they're the same bird then it can't (still) be a first-winter!






Wigeon, Salthouse (Norfolk, UK), 22nd February 2014





Wigeon, Salthouse (Norfolk, UK), 1st December 2012







Wigeon, Salthouse (Norfolk, UK), 23rd December 2015


So what is it, if not a first-winter male?  I missed a clue from the start that this wasn't a first-winter, I think.  The wing-coverts have - and have had since I first saw it - clear whitish fringes.  I believe first-winters should have browner fringes, less clear-cut than these.  It can't be an adult male with these non-white wing-coverts, so it must be an adult female.  But it has male-like grey feathers coming through on the scapulars and flanks, and the head is more solid reddish brown than I would expect on a female.  I think there's even a hint of the cream crown - just faint, but looking rather like it can on first-winter males where it's just beginning to come through.  In fact the pattern of grey male-like feathers does make it look a lot like a first-winter male - it wasn't completely stupid of me to jump to that conclusion when I first saw it!  Here's a first-winter male (already with white wing-coverts) that looks fairly similar:


first-winter male Wigeon, Horsey (Norfolk, UK), 17th December 2011


So the Salthouse bird is an adult female with some male features - an intersex, presumably.  But I had the impression that intersex birds develop over time, becoming more male-like as time goes on.  This bird is no more male-like now than it was four winters ago, so that seems surprising if it is an intersex - but what other explanation can there be?  Do some intersex birds only ever go so far towards male-like plumage?

Closer inspection reveals some other features that don't seem quite normal on male or female Wigeon.  The extent of dark barring on the breast is greater than I would expect, though this is normally variable on Wigoon.  There's also a bit of dark barring on the fore-flanks.  Maybe these are features thrown up by intersex Wigeons?  There is precedent for that happening with intersex ducks - intersex Pintail can show dark barring on the flanks, unlike any normal plumage of Pintail (eclipse male comes closest).

And the white on the head?  Is it too big a coincidence that one bird should show two different abnormal conditions (leucism as well as intersex)?  Probably not - intersex birds seem to be more prevalent among birds already suffering from some kind of abnormality, e.g. in hybrids or selectively-bred mutants.

If this is a female developing male characteristics, are we right in calling it intersex?  Or are there other conditions that lead to the same phenotypic outcome?

Thursday, 26 March 2015

Brown-bristled Marsh Tits?

A recent post on BirdForum drew attention to a new feature for separating Marsh Tits and Willow Tits.  The claim is that Marsh Tits always have black nasal bristles whereas Willow Tits have brown nasal bristles once they mature (young birds may have black nasal bristles like Marsh Tits).  See posts #10 & #11 on this thread.

On Saturday I had the opportunity to watch and photograph several Marsh Tits coming down to seed at Lynford Arboretum.  Lynford has certainly hosted Willow Tits in the past and is not far from where Willow Tits continue to persist, but whether any recent claims of Willow Tit there have been reliable or not, I am not sure.  While I was watching I didn't see anything that made me suspect Willow Tit.  When I used to see both species regularly I found the bull-necked appearance of Willow Tit to be pretty reliable and quite different from the more delicate and elegant Marsh Tit (at least more reliable than the recent literature suggests it should be - but I do agree with these papers in so far as it's a subjective feature so easy to misapply, especially if identifying from photos).  Another feature that's dissed in recent literature is the wing-panel.  Well rightly so as there's huge overlap, but then again I wonder if birds at the extremes might be identifiable on that feature alone?  Anyway, I digress - my point is that all the birds I saw looked like Marsh Tits.  Many of them called and I definitely only heard Marsh Tits.  I suppose it's not impossible that a Willow Tit sneaked in without calling while I was looking through the camera lens rather than paying attention to what the bird looked like, but I doubt it.

These are some of my pics:











Marsh Tits, Lynford Arboretum (Norfolk, UK), 21st March


Some of these birds seem to have black nasal bristles, like they're supposed to.  But a couple of them seem to have at least a slightly brownish tone to the nasal bristles.  It's very subtle, but I don't think it's just my imagination - can you see the brown in these?



Marsh Tits, Lynford Arboretum (Norfolk, UK), 21st March


The first of these two is a tight crop of the second photo above.  The pale spot on the mandible isn't obvious in this photo but it is in the other photos of the same bird (including the top photo of the six above).  In any case it looks like a pretty standard Marsh Tit and doesn't have anything to make me think it might be a Willow Tit.  The second is a tight crop of the fifth photo in the set above (same bird in the fourth photo too).  That bird does look a bit more Willowy in the photos, structurally, but I didn't pick that up in the field.  It also shows a clear and strong pale mark at the base of the upper mandible which, while not held out to be 100% reliable, is surely a pretty clear pointer to this being a Marsh Tit.

Now I don't think the brown tones on my birds here are as strong and clear as they are in Ashley's photos of brown-bristled Willow Tits on BirdForum.  But to my eyes there's a clear contrast between the slightly brownish bristles and the blacker forehead and crown, especially on the lower photo.

What does this mean?  Four possibilities so far as I can see:
  1. Brown bristles on a Marsh/Willow Tit is not a reliable means of identifying it as Willow Tits, contrary to Ashley's claim on BirdForum.  I know Ashley is experienced with both species but I don't know how extensive his data is on which he has based this claim.
  2. It IS a good feature but instead of saying black for Marsh Tit we should say black or blackish brown - as distinct from the more clearly brown of Willow Tit.
  3. It is a good feature but can be misleading in photos.  Mine aren't of the finest quality and some colour aberration in the photo may have contributed to a more brownish appearance, which is more evident in the bristles which were a subtly different shade of black.  Not convinced, but I throw it out as someone might want to make the case for it.
  4. My birds are Willow Tits.  I'm sure they're not, but I'm capable of being wrong.
  5. My birds are hybrids.  Being a hybrid nut I like this idea, but I don't seriously think it's likely.  Worth thinking about though, especially if the evidence for Ashley's claim is robust and black really does mean black, as opposed to blackish brown. 
There may be other possibilities - let me know if you think so.

If possibilities 2 or 3 are the explanation then this has implications for how we should apply Ashley's new feature, and clearly considerable care is required (and much more so if possibility 1 is the answer).  I am personally content to rule out possibility 4.  I think we need more understanding before embarking too strongly on the hybrid theory, though I would point out that (a) hybridisation between these two species has been reported, and is very likely to be overlooked when it does occur so can be expected to be massively under-reported; (b) hybridisation between other Poecile species (e.g. in North America) occurs quite frequently and (c) hybridisation is most likely in places where one species is either spreading into an area already occupied by the other (not relevant here) but perhaps also where one species is withdrawing from an area still occupied by the other (possibly very relevant here).

What do you think?

Thursday, 22 January 2015

Brood manangement of Hen Harriers: working with or working against?

A slight diversion from the stuff I usually blog about.  This post has nothing to do with identifying birds or how birds appear.  It has to do with conservation, and how different approaches to conservation work together - or not.

Here's the thing.  There's always been a tension between the conservation and birding communities and the shooting and gamekeepering communities.  One view from conservationists is that they should work with and influence shooting/gamekeepering communities, another is that they should fight against them.  I'm not sure what the right answer is, but what I see happening this morning is definitely not the right answer.  What I see this morning is conservationists who want to fight against shooters fighting against conservationists who want to influence shooters.

In the good old days I was under the impression that most conservationists and conservation bodies (like the RSPB) took the approach that while they didn't really like people shooting grouse, they recognised that the people who shot grouse maintained grouse moors, and that was prerequisite for grouse to survive - and that in turn allowed their predators to survive.  I thought the thinking was that if you stop grouse shooting you stop grouse moor maintenance resulting in loss of grouse habitat, loss of grouse and loss of harriers.  Maybe that wasn't the official stance - maybe it was just what a few people I mixed with told me, but it was the view I was exposed to when I was growing up and I bought the argument - it made sense to me.  And I thought conservation bodies like the RSPB were seeking to work with landowners and gamekeepers and the shooting community in general.  It was a fragile relationship for sure, but one they thought was worth persisting with.


Red Grouse, Cumbria/Co Durham border, 30th December 2011


Only in recent years has the tide of opinion seemed to change.  Recently the overwhelming majority view that I'm exposed to is that there is no working with the shooting community.  They are all bad, through to the core.  And now the popular approach for conservationists is to aggressively and activley oppose the shooting community and to campaign against grouse shooting in particular.

If I've read things right, many conservationists have decided that they've spent enough time and effort trying to partner with the shooting community and gamekeepers and have become so frustrated that their efforts have come to nought that they've given up that approach and switched to a new one.  It's the opposite to "if you can't beat them, join them": it's a case of joining with them isn't working so we'll beat them instead.

I don't know what the right answer is.  Breeding Hen Harriers have been all but wiped out in England and the shooting and gamekeepering community continue to spout utter nonsense in support of killing raptors.  The notion that a healthy population of predators can decimate  whole populations of their prey and remain healthy themselves, and that killing predators will somehow save our songbirds is as absurd as anything I can imagine, yet it is promulgated endlessly by gamekeepers and shooters.  Gamekeepers are being prosecuted and found guilty of killing raptors and their communities denounce their crimes in the most thinly veiled supportive way they think they can get away with.  I can certainly understand why conservationists have lost patience with them and switched to outright opposition.  Is there any point in persisting with a collaborative approach?

It seems that the Hawk and Owl Trust think there is.  They're supporting a proposal to allow brood management of Hen Harriers under certain conditions which, they believe, will offer sufficient benefit to Hen Harrier conservation that it will outweigh any disbenefit of brood management.  Brood management means that if two broods of Hen Harriers hatch within specific proximity of each other the second brood is removed and raised in an aviary before being released in suitable habitat after fledging.  One condition is that all remaining chicks must be satellite tagged which (a) allows monitoring and (b) deters shooting.  The other conditon is basically that members of the gamekeeper organisations behave themselves.  You can read about it here.  I don't honestly know if it is a good idea or a bad idea, but it doesn't seem unreasonable.  More to the point, it seems that it was a thoroughly and properly considered idea that is intended to support Hen Harrier conservation.


Hen Harrier, Sheringham, 29th October 2011


Mark Avery is now a prominent figure in conservation.  He worked for the RSPB for 25 years and for most of that time was the RSPB's Conservation Director.  Maybe it's just because of the advent of social media, but he seems to me to have come to greater prominence since leaving the RSPB four years ago.  I only started to become aware of him towards the end of his time at the RSPB when I became increasingly concerned about some specific conservation policies that the RSPB were adopting under his leadership (particularly their partnership in the misguided and thankfully now abandoned project to introduce White-tailed Eagles into East Anglia).  I don't remember seeing it when he was still at the RSPB and maybe his independence has given him the freedom to be more public about what he really thinks, but new or not he is now pretty vocal in his opposition to the shooting community.  Maybe I just missed it before - I never found the RSPB magazine a great read (that's not a criticism - I support it targeting people who aren't already dedicated birders) and Twitter didn't exist, but now at least his approach seems to be an all out war, burn the bridges and don't even think about partnership or collaboration.  He gets a lot of support for that approach and with patience with the shooting community at an all time low it's little wonder he does.

Mark Avery may have done a lot of good and much of what he says and does may be of real benefit to conservation.  He may deserve the prominence and support that he enjoys and maybe he even deserve a knighthood as I saw someone suggesting recently.  But I don't think he deserves it for his blog post this morning.  In it he attacks the Hawk and Owl Trust for their stance on brood management of Hen Harriers.  He doesn't simply argue against their stance (I wouldn't mind that but he doesn't even do that very persuasively) but he attacks the trust.  Because the trust have a different more collaborative approach then he does they must be on the shooters' side.  Or on the landowners' side as he characterises that (not entirely without justification, I suspect, but unhelpfully here).  Their chairman might be a landowner but maybe that's a positive not a negative.  Maybe that gives them an opportunity to influence landowners in a way that promotes conservation far more effectively than burning bridges and trying to destroy them.

Just to remind you, according to their submission to the Charity Commission, the Hawk and Owl Trust "works to conserve wild bird of prey and their habitats and to encourage people to enjoy and understand these special birds.  It carries out its objectives through creative conservation, practical research and imaginative education."  From what I've seen of them at Sculthorpe Moor that sounds about accurate.

I don't know which approach to conservation is the right approach.  I don't know if we're best off attacking the shooting community or finding common ground and influencing them.  But I'm pretty sure that conservationists attacking conservationists isn't the right approach.