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!

Friday, 13 December 2013

Pied Flycatcher in Iberia

Well I didn't get much response on my last post about a Pied Flycatcher so let me try another...

Pied Flycatcher, Ebro Delta, 20th May 2013

This one was in Spain, by the visitor centre in the Ebro Delta, in May 2013 (I've only just got round to sorting the photos out).  It wasn't in suitable breeding habitat so can be assumed to be a migrant.  As such I imagine (but don't know for certain) that the nominate hypoleuca is more likely than the Spanish iberiae.

One feature caught my attention: the pattern at the base of the primaries.  I was looking to check the size of the white patch at the base of the primaries.  In itself the white patch was not especially remarkable but what was more interesting (to me) was that around it, covering an area more comparable to the more extensive white patch of a Collared Flycatcher, was a diffuse pale patch - contrastingly browner than the smaller clear-cut white patch but also contrastingly paler than, though diffusely separated from, the dark brown colour of the more distal section of these feathers.

I don't remember seeing that before.  That doesn't mean it's unusual - just that I've not noticed it.  Maybe I haven't looked hard enough - quite possible.  I checked quite a few images, of my own and on the internet, and at first couldn't find others like it.  Eventually I did find some, including breeding females photographed in England and in Russia.  So probably not unusual and clearly not an indicator that it might be anything other than nominate hypoleuca.

In the meantime though I tried to research how to identify female iberiae, just in case it hadn't turned out to be ok for hypoleuca.  I found very little info on ID of female iberiae.  In fact the only reference I could find on separating female iberiae from nominate hypoleuca was BWP which states that in female iberiae the tertial margins are much broader than in female nominate hypoleuca, forming small white wing-patch.  Well the white tertial edges on this bird are pretty broad and they form a white patch, but are they too broad for hypoleuca?  I'm not convinced, though there are certainly lots of photos of spring female nominate Pied Flycatchers on the internet where the white fringes are narrower.  Here are some more views - what do you think?

Pied Flycatcher, Ebro Delta, 20th May 2013

Are there any other differences between the two forms to look out for?

Tuesday, 20 August 2013

A Sparrow that looks Italian... but is it?

I've blogged about Italian Sparrows before, but I didn't expect to be blogging about one here in Norfolk!  On Sunday I popped up to see the sparrow at Northrepps that seems to show characteristics of the Italian form italiae, now treated by many authorities as a new species formed by hybrid speciation (i.e. a population of hybrids, in this case Spanish Sparrow x House Sparrow hybrids, that have become sufficiently reproductively isolated from either ancestor species to be treated as a new species).

 Italian-type Sparrow, Northrepps (Norfolk), 18th August 2013

It looks good!  But is it really an Italian Sparrow?

Here are the options...

1) Hybrid Tree Sparrow x House Sparrow has been suggested.  They occur occasionally so it wouldn't be all that exceptional - certainly more likely than an Italian Sparrow.  But other than lacking grey in the crown this bird doesn't really resemble Tree Sparrow.  Most (if not all) Tree x House Sparrow hybrids have grey in the crown, most have at least a hint of a dark cheek spot, most show buffier tones on the body, they should probably have a smaller bill than this bird.  I don't see anything to suggest Tree Sparrow involvement in this individual.

 Italian-type Sparrow, Northrepps (Norfolk), 18th August 2013

2) An aberrant House Sparrow.  This bird shows reddish-chestnut extending on to the breast band and the white supraloral stripe is virtually absent.  That could be explained by an excess of whatever pigment causes that chestnut colour (is that erythrism?) and if it has that sort of pigment issue then perhaps it could be affecting the crown too, flooding that with chestnut colour?  I think this suggestion deserves some merit, but it doesn't convince me.  It's not extremely unusual for House Sparrows to show very white cheeks, and perhaps the bill bulbous bill is within range for House Sparrow, but what are the odds of a House Sparrow with erythrism generating a completely chestnut crown like an Italian Sparrow also having white cheeks and a big bulbous bill?  I can't rule this option out, but I find it rather unlikely.

  Italian-type Sparrow, Northrepps (Norfolk), 18th August 2013

3) An Italian Sparrow, i.e. a vagrant from Italy or neighbouring regions.  Some features need explaining for this option, namely the chestnut on the breast, the restricted white supraloral and what looks like grey flecking in the crown.  The breast is easy - quite a few photos of Italian Sparrows have this.  It's not typical but it's not exceptional either.  The restricted white supraloral seems to be more unusual, but there are images online that seem to share this feature.  At least some of the grey flecks in the crown are not true plumage features but an effect of moult.  The bird has several loose or missing feathers and this seems to be revealing grey feather bases.  I'm not convinced that there really are any grey feathers in the crown, although this will perhaps become clearer when the bird has completed its moult.  So nothing here rules out Italian Sparrow, but we can't get away from the fact that it's not a completely typical Italian Sparrow.  If the odds of any Italian Sparrow turning up in a Northrepps garden are low then I'd have thought that the odds of one with chestnut on the breast and virtually no supraloral stripe are significantly lower.

 Italian-type Sparrow, Northrepps (Norfolk), 18th August 2013

4) A hybrid between a House Sparrow and a Spanish Sparrow.  There are a few references to hybrids between these species away from Italy.  Spanish Sparrow has occurred in the UK several times and some have been long-stayers oversummering with House Sparrows, so one producing hybrid offspring isn't very unlikely.  Sparrows tend to frequent places that aren't birding hotspots so it's plausible that even a male Spanish Sparrow could have summered and bred locally without being detected - and most birders would be hard-pushed to detect a vagrant female even if it was breeding in their own garden!  It's a pretty subjective call whether a hybrid Spanish x House Sparrow would be more or less likely than an Italian Sparrow to appear in Northrepps, but I am personally inclined to think such a hybrid might be rather more likely than a vagrant Italian.  As yet I haven't been able to track down any photos or descriptions of Spanish x House Sparrow hybrids, so I'm not sure how their appearance fits in with that of the Northrepps bird.  Given the history of Italian Sparrow it seems reasonable to summise that they look a lot like Italian Sparrows, and given that first generation hybrids between any two species (not in every case) tend to be a bit variable we might expect that it will look a lot like an Italian Sparrow but not necessarily exactly like a typical Italian Sparrow.  In other words they might look a bit like the Northrepps bird, perhaps.  But all that is guesswork - I don't actually know what Spanish x House Sparrow hybrids really do look like.  If you can point me to any references that show such a hybrid (proven or not) please leave a comment or get in touch!

 Italian-type Sparrow, Northrepps (Norfolk), 18th August 2013

Whatever it is it's an interesting bird - big thanks to Andy and Carl for finding it, letting us know and allowing me to visit.

Maybe DNA analysis will offer some answers in due course...

Wednesday, 10 April 2013

"Green" Pheasants

For several years I noticed increasing numbers of reports of Japanese Green Pheasants in Norfolk, but when I eventually started seeing these birds, something didn't seem quite right.  I've never been to Japan, and have never seen a real Green Pheasant, but in the photos I've seen they've had pale blue wing-coverts and a pale blue rump.  The birds I was seeing were superficially similar, but they weren't quite right.  Sometimes they looked green, but in some lights they looked blue or purple - or even black.  Notably the wing-coverts and rump always seemed to be more-or-less the same colour as the rest of the wings and body - or at least not significantly paler as they should be on Green Pheasants.

A bit of research first turned up information about "melanistic" Pheasants, and these reports clearly related to the birds I was seeing.  A bit more research uncovered talk of Pheasants of a mutant variant known as 'tenebrosus'.  These were the same birds, and apparently it wasn't strictly correct to call them melanistic.

Pheasant (var. 'tenebrosus'), Ringstead, 25th March 2013

I've not managed to determine the origins of this variant.  Some reports hint at the possibility that there are some Green Pheasant genes present, but so far as I can tell this idea is based only on speculation from its appearance rather than any firm evidence (but please correct me if you know otherwise).  Green Pheasants and Common (or Ring-necked) Pheasants are of course closely related - variably treated as either a subspecies or full species - so they doubtless have similarities in their genetic make-up.  A mutation in one species could easily result in the bird throwing up features normally associated with the other species.  I suspect that's the explanation, rather than them being hybrids.  And as with domestic duck breeds, when a mutant has characteristics that are desired by keepers birds are selectively bred to establish these characteristics.  That seems to be what's happened, and the result is Phasianus colchicus var. 'tenebrosus', or Tenebrosus Pheasant.

However they came to be they're stunningly beautiful birds.  I've noticed that they seem to become quite common in an area for a while and then disappear, presumably because the local gamekeeper has favoured them for a bit and then they've either died out or they've lost favour with the gamekeeper for some reason.  Outside of these localised patches of abundancy they seem to be fairly widespread and not desperately uncommon - I see odd birds at widely scattered locations from time to time.

Here are a few males:

Pheasant (var. 'tenebrosus'), Coxford, 26th March 2013

Pheasant (var. 'tenebrosus'), North Creake, 26th March 2012 

Pheasant (var. 'tenebrosus'), Great Hockham, 12th March 2006 - one of the first birds I saw well.  At around this time Tenebrosus Pheasants seemed to outnumber ordinary Pheasants in this area but in recent visits to the area I've not seen any

Pheasant (var. 'tenebrosus'), Hockham, 14th February 2009

Pheasants (var. 'tenebrosus'), south of Wells, 13th April 2011 - there were loads here in spring 2011 but I've not seen any on subsequent visits

Some birds have a few paler brown markings along some of the feather shafts.  Not sure if a breeder would regard such birds as 'pure' Tenebrosus or not.  This one's pretty close if not:

Pheasant (var. 'tenebrosus'), south of Wells, 13th April 2011 

The brown internal markings on some of the feathers of this bird are a bit more obvious.  Still a Tenebrosus?

Pheasant (var. 'tenebrosus'?), Saham, 17th March 2012

I've been able to find remarkably little information about what females are supposed to look like.  But I have seen a lot of dark female Pheasants, often in the same places as I've seen male Tenebrosus Pheasants, so I presume that's what they are.

Supporting the argument that the often-used term "melanistic" isn't technically correct for these Pheasants, many of these dark females show obvious pale fringing on the feathers, despite the brown base colour being much darker than on normal Pheasants.  Here are a few:

Pheasant (var. 'tenebrosus'), Anmer, 6th September 2011

Pheasant (var. 'tenebrosus'), between Flitcham and West Newton, 20th February 2009 - not sure what the significance of the bluey patch around the eye is - this isn't a typical feature of any form of Phasianus colchicus so far as I know

Pheasant (var. 'tenebrosus'), North Creake, 8th April 2011

Pheasant (var. 'tenebrosus'), Wolferton, 21st March 2011 

Notice how the females seem to often show an irridescent purply patch on the side of the neck, a feature absent from normal female Pheasants.