But Lindsay's clear point "It is now fairly evident that many of the birds that DNT and Alan Knox referred to as "Scottish Crossbill" are in fact what we today call "Parrot Crossbill" here in Scotland" — the really thick-billed birds one sees in Scotland are not, and never have been, "Scottish Crossbills". I've not seen Hartert's specimen either, but it obviously needs re-examination in light of the new data.
Michael ( it is Michael, right ?

) the caveat I used is "many" ! Alan (and possibly Desmond) also miscategorised some Commons as "Scottish" which just shows how important physical evidence (Biometrics and Calls) are in making a classification. The fact that it was assumed
scotica was biometrically intermediate is what has caused this. However, there are 'intermediate' crossbills in Scotland.
On the comments about "Scottish" being a type of Common Crossbill, it is certainly possible, however it would be unusual in that putative
scotica is sedentary unlike other
curvirostra that are only present for a few months and then move away - Marquiss and Rae showed this with ringing data of birds trapped in Deeside. On the other hand, birds that have been ringed and biometrically classified as
scotica (and my case sound recorded !) have been retrapped years later. In my case, I have physically retrapped two
scotica type birds at exactly the same site 4 years apart - one of them with Dr. Ron Summers, details here:
http://pinemuncher.blogspot.co.uk/2010/07/catching-pine-crossbills-upper-deeside.html
I also have re-sighting data from colour-ringed birds.
So, if what we currently classify as
scotica is a Common type it would be unique in that it is sedentary, and indeed it would appear to be endemic.....you can see where I am going with this !
Regarding Parrot Crossbills colonising from continental Europe it is certainly possible. However, no Scottish birds that have been ringed have turned up anywhere else (including England !). Also, why did all these birds that turned up two winters ago down south not colonise, surely there is sufficient habitat ? The Norfolk birds in the 80's actually bred successfully, so again why was a viable population not established ? My understanding from collected evidence is that continental crossbills (both Parrot and Common) will irrupt, possibly breed and then move. My theory is that the population of large billed crossbills in Scotland, "Scottish Parrot Crossbill", have been there for a very, very long time. To perhaps highlight the sedentary nature of 'Scottish Parrot' I saw a colour ringed Parrot in Glen Derry in 2005. I reported it to Robert Rae who informed me it was ringed at that very location.......in 1986.
The 'Scottish' type call that was recorded in Kielder Forest that Nutcracker keeps mentioning I would very much like to see/hear that. I reckon it would take all of several seconds to shoot it down.
John, there are variations in crossbill calls within a 'type' that may similar to the dialectic variation in Great Tits and Chaffinches that you keep going on about. However, the differences between actual call types would be similar to that of a Great Tit to a Coal Tit. If you want to send me examples of this dialectic variation, or point me to recordings that you think exhibit it, I will gladly produce sonograms of the supposed variations. It is too simplistic and naïve to assume that all variation in crossbill calls is merely dialectic, though it may explain subtle variations within the call types.
Lindsay