Thursday 27 August 2009

You Say Parrot I Say Potato

"Shurely a Parrot Croshbill Mish Monneypenny" ?

Following the BBRC decision to remove Parrot Crossbill from the BBRC list as outlined previously on this blog, and also reported in British Birds May Vol.102 p.275, the debate has ensued as to whether or not this is a good decision. There are some sensible points discussed HERE, though I am not sure about posts # 44 and #45 - and there was me thinking I was such a friendly and amiable chap ( which I am when you get to know me.....honest) !

For me BBRC decison on Parrot Crossbill is a kind of revelation, as last year the editor for the North East Scotland Bird report quite correctly insisted that I add a caveat in the text that none of my Parrot Crossbill records had been submitted for review by BBRC. So were my Parrot records credible ? This was my primary concern as, without the blessing of BBRC, these 'unverified' records (all mine !) could perhaps be seen as vague at best - "stringy" is the correct term, as I understand ? However, we all know that biometrically and bio-acoustically "Parrot" type birds have been getting trapped and sound recorded in Scotland for well over a decade. Thus back to the BF debate, which sadly I can't take part in. I sit on both sides of the fence on this one for the following reasons:

My own records of Parrot 'type' Crossbills now gain credibility and there is now an acknowledgement that Parrot type birds breed and are resident in NE Scotland, differentiated from 'migrant' records. Hooray, result !


Presumably all records submitted by other parties will also be accepted without verification ? But,what if these are mistaken or errant - given the ongoing confusion amongst most birders between Parrot, Scottish and even Common is this a wise policy ? Also, what about 'true' migrant Parrot type birds on Fair Isle or the Norfolk Coast - do BBRC not want descriptions of these either ?

Now, this really makes me sound omnipotent and selfish, doesn't it ? Basically, what I can be accused of saying is that I can ID Parrot Crossbills and nobody else can ? Well no actually, that is not what I am getting at, and far from it really. It is not that 'other' records can't be trusted but, in my defence, a lot of pictures I see of 'Scottish Crossbills' on the web, and even published articles, appears to be one of these Parrot type birds. So, if someone reports a specimen as Scottish Crossbill then it is, in all probability, very likely a Parrot Crossbill ! This may work in everyones favour regarding accuracy eg. a big billed bird is most likely a Parrot type, however some Scottish types do appear to overlap with the smaller end of the Parrot size range - at least they are considered as Scottish just now, but may be a modal bill size all of their own. Readers may remember a long since hacked and deleted post on this blog about a large billed crossbill sighted in Wales by Dan Brown ? My advice was that although the bird appeared to have a large mandible this could have been out of proportion to it's body - a small bodied bird with a disproportionately large bill can look 'Scottish' or 'Parroty'. There is a good example in Birds of Scotland of a profile of a Scottish type bird with a HUGE honker of a beak in the photo, yet it's bill depth was bang on for Scottish. It clearly had 'big beak, smaller head' syndrome !

Scottish, Parrots or Common? Ask the audience? Phone a Friend? Final Answer ?

For those sound recording to verify their 'observations' the flight calls are also very confusable, as I see time and time again - according to Knox, and Constantine and Mullarney, Parrot flight calls in Fennoscandia and on the continent can be quite variable, though I am not sure if they confirmed this with biometrically verified birds. Magnus Robb has also recently recorded some variation in Parrot Crossbill call types from several different irruptions into Holland. In Scotland there does seem to be some variation with Fc2. Poor sound signals can result in calls losing important structural features and frequency can vary with distance, and, it seems, simply by natural variation within a call type. Thus, these calls are easily confusable on sonogram. By ear, without much experience or suitable comparison, it would be very easy to confuse Parrot EcD with Common EcA, the latter sounds slightly higher, hollower in timbre and with more obvious harmonics - but what does that actually mean in the field ! ? Parrot Fc2 can also be very easily confused with the thinner "Cheepy" Fc1 of Common Crossbills that are prevalent up here in Scotland just now, both on sonogram and 'by ear'.

However,with tangible physical measurements such as biometrics or a sound recording a record can be updated or reviewed in the future should our knowledge change regarding crossbill speciation. A statement " 5 Parrot Crossbills at Anagach Wood" cannot. It simply infers that there were (possibly) several big billed crossbills there. Photos help to some degree but can be misleading - lots of shots of the same individual from different perspectives are often required.

Back to the Bird Forum debate and some of the comments, some of which mention me personally. James Spencer (Hotspur) writes in post #5 :

"If you adhere to Lindsay Cargill's identifications then most of the Scotsbill in the various bird galleries are actually Parrot Crossbill".

Yes and no James - I have basically suggested this as a generalisation, but I have not identified every single photograph on the web ! There clearly are some Scottish Crossbills on web galleries - there are even some of mine on the dreaded Bird Forum ! Granted a large amount of birds labelled as 'Scottish' would be classed as 'Parrot' type by me using my own experiences and under currently accepted classification and thinking here in Scotland eg. bios and calls as they stand.

In post #25 Richard Klim writes:

"Laurent Raty made the following comment during a recent ID-Frontiers discussion about the recently-described South Hills Crossbill (suggesting that Parrot is now more likely than Scottish at Abernethy):

"... medium-size-billed crossbills in Scotland [Scottish crossbills] are now found largely in alien conifer plantations, rather than in native Scots pine forests where they are supposed to have evolved [and where bigger-billed birds now occur]."

The quote by Laurent, a very knowledgeable and nice chap, regarding medium sized birds is an extent ! Scottish can occur in alien conifer plantations but generally at particular times of the year. This caveat is very important: In February scotica is usually back on territory in either native or plantation Scots pine. The problem being so is curvirostra, though some will feed on Larch until April if it is still present - this winter the Commons, and Scottish for that matter, were predominantly found on Scots pine throughout the year due to a Larch and Spruce crop failure. Scottish will move on to Larch in late summer and early Autumn and will flit between Larch and Scots Pine through the winter. They will aslo subsist on Spruce, particularly Norway if present, and Lodgepole.

However, all of this potentially gets even more complex, and this is my point: how may people are mistaking Common Crossbills for Scottish Crossbill ? Parrot and Scottish are always considered the ones that are confusable, but in reality it is probably Common and Scottish (under current classification criteria) that cause most problems. The female bird in the top banner of Loxia Fantastica is a second calendar year Scottish Crossbill. Be honest: how many of you would have had that down as Common ? The bill shape is not typical Scottish, certainly not from that angle, but the plumage definitely is, though Common's feeding exclusively on Scots Pine may also appear 'dusky'. The bird gave a Scottish type call.

In balance I think the BBRC decision is the right one - a few misidentified specimens of either species will be overshadowed by the hundreds of verified (but not submitted records) that crossbill researchers and enthusiasts collect, that till now have always been in a dodgy 'are they aren't they' area ! Bear in mind most of my records are confirmed by either calls or biometrics (colour ringed birds that have previously been trapped). Actually, in my opinion they still are in that 'dodgy area' for reasons cited in a post way down below regarding the possible identity of the true relict Pine Crossbill of the Great Forest of Caledon ( just my thoughts, half baked maybe), but at least it gives us an position to move on from should classification be altered in the future. 'Parrot Crossbill', in my book, is merely a label for the largest billed crossbills that exist in Scotland and also on the continent. The Scottish 'Parrot Crossbills' may be the 'same stock' as their continental counterparts, though maybe they are not, and are actually the real relict 'Scottish' pine wood species. Certainly food for thought I think