Scottish Crossbill (1 Viewer)

Michael Frankis · Oct 24, 2003

Hi Alastair,

Alastair Rae said:
Lack of difference in DNA seems pretty good reason for a lump. After all Danish people are statistically a different shape to Irish people and sound different. But their DNA is more or less identical.

Better try me and Harry together to test that hypothesis! (well, gotta be honest, I'm a hybrid Danish x English

)

Alastair Rae said:
Didn't a BB paper a couple of years ago say that Common Crossbills can have different bill sizes depending on the type of forest they live in? Are the phenotypical differences down to environment rather than genes?

Not I guess in that sense - there's three different Common Crossbill call types, equating to three different taxa (and no reason why not as distinct from each other as they are from Scot & Parrot), but how these relate to different forest types isn't currently known.

But if they're going to be lumped, you have to include Two-barred as well - that shows no more DNA difference than any of the others. And when you do that, things get a mite tricky . . . you have awkward questions like how they maintain their plumage differences.

So realistically, there's only one species of crossbill on the UK list, or else six. A bit of a nightmare for the field birder!

The working assumption being used by the groups studying the crossbills is that they haven't yet found the part of their DNA that codes for the differences that keep them distinct (only a small part of their genome has been studied to date).

Michael

HH75 · Oct 24, 2003

Hi Alistair,
I dare say that Michael and I belong to the same biological species,but may yet be split under the PSC...?;-)
I would be loath to lump Two-barred with the rest,as it is quite distinct with respect to plumage(other than the obvious wingbars,terial pattern etc males are also a different shade of red,and the bill is thinner),but would also be sceptical of a split of Common Crossbill into three(or more)based on call types(which can only reliably be differentiated based on sonograms),but,of course,whatever taxonomic solution best fits the actual situation is the correct one,regardless of what birders "want"!
(On this topic,it's interesting that arch-splitter Lee Evans treats Scottish Crossbill as a subspecies of Parrot on his UK 400 club website,perhaps reflecting the unease among birders towards recognising a species that cannot be identified in the field,or often in the hand)
Harry H

Michael Frankis · Oct 24, 2003

Hi Harry,

The white wingbars etc is 'real', but the different shade of red is dietary, as the red colour is made up of anthocyanins and erythrosins in their food.

I've not read anything on how they get this (conifer seeds are white inside, so it can't be from this). My personal suspicion is from eating pollen cones and/or immature female (seed) cones in the spring shortly before the moult (I've seen crossbills do this, and immature conifer cones are rich in these pigments).

Particularly striking with the Parrot-type crossbills I saw in Bulgaria, where the males were a very distinct pink-purple, almost certainly related to the dark purple cones of the Balkan endemic Pinus heldreichii.

Michael

Michael Frankis · Oct 24, 2003

And on a lighter note . . . . 3

Harry Hussey said:
I dare say that Michael and I belong to the same biological species,but may yet be split under the PSC...?;-)

Can't tell, as you've not posted in the 'members' faces' gallery yet! o

And if you ever want to demolish a PSC proponent, just ask how many species he splits Homo sapiens into - it is one of the biggest problems for the PSC! :brains:

Michael

birdman · Oct 24, 2003

Not disagreeing with you at all Michael, as I am nowhere near experienced enough to do so, but....

if the red feather colour of Crossbills is due to dietry pigmentation, why are the females green?

(Probably a stupid question, so please be gentle with me!)

Michael Frankis · Oct 24, 2003

Hi Birdman,

Not a stupid question at all - simple answer from me is, I don't know!

Two obvious possibilities are (1, most likely) the females digest (break down) most or all of the pigments they eat, perhaps needed by them for nutrition towards egg development, perhaps evolved so they are better camouflaged, and (2, less likely) they don't eat the immature cones in spring at all (seems unlikely, as this is a nutrient-rich food source at a time when most seeds are shed & gone).

Can add that the same applies to other finches with sexual colour dimorphism (Linnet, etc)

Michael

HH75 · Oct 24, 2003

Hi Michael,
Was only extracting the urine with the PSC remark:we couldn't even be split on that score,as we're both Caucasians.Will post a pic soon(you have been warned)
Birdman:I'd guess that the sexual dimorphism is real,and that females(and imm.males)are green to provide greater camouflage,with the male birds using their bright colouration to attract females.Why the diet should affect the actual colour of males and not of females is a mystery to me

erhaps males purposefully seek out pollen cones etc(by instinct,not design!) to increase the intensity of red attained?
Harry H

Michael Frankis · Oct 24, 2003

And don't ask me why Redpolls are red, and Siskins are green, I don't know that either!!!

Michael

Tom Moodie · Oct 27, 2003

See British Birds, January 2002. A study in Abernethy Forest from 1995-2001 found that 74% of Crossbills trapped were Parrot and only 8% were Scottish.
Also article in Birding Scotland, August 2003 on un-identified crossbill that may have been Two-barred or Common finishes with the quote: get your tape recorder out, only that will provide the crucial evidence you will need to id you crossbill. From all this I would say that answer to initial question is almost certainly NO.

Tom

Julian Sykes Wildlife · Oct 29, 2003

Aye, great debate. But who has it their British and/or Scottish lists, quite a few i suspect!!!. I do, but i'm an optimist, i've seen well over 100 crossbills around that area so i must have seen 8 Scottish Xbills. Works for me.

Acanthis · Feb 24, 2004

I know this is an old thread but crossbills are my current obsession and I had to get involved:

Michael Frankis said:
Should of course clarify this - if a bird gives a 'Type C' call (as per Brit. Birds 96: 100-111), then it is a Scottish Crossbill.

That is, if Hartert's museum specimen which defines Scottish Crossbill also gave a 'Type C' call when it was alive.

Which of course, no-one can ever know . . . . maybe it didn't . . . so in that sense, Scottish Crossbill cannot be identified, ever (other than one skin in a museum) . . .

Michael

Absolutely right! And this possibly also applies to most other named crossbill taxa. Even the original Loxia curvirostra could be invalid since its vocalisations weren't recorded. If crossbills are to be reclassified vocally then surely most subspecies, forms etc will need to be renamed.

Acanthis · Feb 24, 2004

stuprice68 said:
We get a lot of ( Common ) Crossbills here in the winter. Maybe they haven't been studied as much as those in Europe. Perhaps there is a Hokkaido Crossbill waiting out there to totally confuse the birders over here ......................

Hi,
Hokkaido Crossbill - You never know!
I'd be willing to bet a few yen that if you were to tape your visitors over a few years you'd find a variety of different vocal types.

Acanthis · Feb 24, 2004

Michael Frankis said:
If I had a decent sound-recording and analysing setup, Yes.

Otherwise, No.

Michael

Hi Michael,
I've been enquiring about that. You can use a combination of a good directional microphone, a cheap tape recorder, and free downloadable software from the net. Doesn't have to cost the Earth!

alcedo.atthis · Feb 24, 2004

> On a visit to the Osprey Centre near Aviemore, Scotland, I looked at
> their species board: among the many listed was "Crossbill spp". When > I asked the staff about it they answered that they didn't know which > Crossbills were around there, because you would have to catch them > to measure their bills, and because they thought that the Common or > Parrot was also around there. When even they don't know......

Peter, I would not read too much into that. In the Loch Garten centre, there were claims, on the board, that the male Osprey had just returned to the nest with a "10lb Brown Trout" Mmmmmmmmmm!!
Flown in special delivery.

Returning to Crossbills, Robert Rae (Leader of Grampian Ringing Group, and Mick Marquis (I think, if memory serves me correctly)) have done a comparative study on Common, etc -v- Scottish. I think there findings were published, but I will check, and as far as I can recollect, they can be seperated. I am sure that they did the DNA as well.

Malky @ Westhill

Edward woodwood · Feb 24, 2004

in response to the original question...

no, not even a slim chance of iding Scotchbill in the field.

I treat all field claims of this 'species' with a heavy dollop of scepticism. The whole Loxia asssemblage is a can of worms, especially when folk start loking for 'new species' in there.......Where is Spud/Logos these days? I'm sure he'd have had some wise words on this topic......

HH75 · Feb 25, 2004

Hi Lindsay,

I agree with a previous poster from Strathspey who reckons the Scottish Crossbill is an evolving remant Parrot Crossbill, but this of course is pure speculation !

If this is the case,then perhaps the reduced frequency of 'intermediate' birds(i.e.'Scottish') could be due to the area being colonised by 'typical' Parrots following a large invasion(perhaps that of 1982?),which then interbred with the 'Scottish' birds(which were,after all,Parrots all along),thus leading to 'classic' Parrot features spreading at the expense of those shown by the already resident 'Scottish' birds?
Of course,this is all speculation on the assumption that your hypothesis above is true: it may not be!
I agree that it would be advisable for birders to continue to look for and document the 'crossbills' in the area,whatever their taxonomic affinities.
Arctic and Mealy Redpolls?That's another day's debate!

Harry H

Acanthis · Feb 25, 2004

Harry Hussey said:
Hi Lindsay,
I agree that it would be advisable for birders to continue to look for and document the 'crossbills' in the area,whatever their taxonomic affinities.
Arctic and Mealy Redpolls?That's another day's debate!
Harry H

Redpolls and crossbills are apparently each other's nearest relatives within the finch family and they share 1 characteristic - the propensity to give people 'splitting' headaches!

I think a good recording of flight + excitement calls would ID any dubious looking crossbills. The best and most comprehensive collection of crossbill recordings I've heard is available on a CD with a copy of Dutch Birding 22: No 2. Not only does it cover 6 curvirostra vocal types but Parrot, Scottish and 2-bar. Even a duffer like me can now confidently ID Common from 'Pine' crossbills by ear, though Parrot from Scottish may take a little longer.

Binocularface · Feb 25, 2004

Hi

A couple of years ago I was in Kielder Forest (Northumberland) and I observed a Crossbill that was intermediate in bill structure between Common Crossbill (which were nearby for direct comparison) and Parrot Crossbill (which wasn't around for comparison!). I first picked the bird up on call as it was noticable different to the calls of the Common Crossbills that were also vocalising. The call of this bird was very similar to birds I have heard in Speyside, that I assume were Scottish Crossbills (deeper (& less 'chirping') than the Common Crossbills).

This certainly through a spanner in the works for me!

Regards
Tristan

Edward woodwood · Feb 25, 2004

Scotchbills cannot be done on bill size due to the considerable overlap that exists

same goes for wing length

there are no diagnostic plumage differences

the are no clusters in mitochondrial DNA hence they are not even genetically distinct....a little bit of this would be expected despite recent possible 'speciation'

only one vocalisation is apparently distinct but could this be a result of interbreeding? The type c call sonograms appear to have characteristics of Common and Parrot! Interbreeding has been 'proved' with a 'Scottish' (though how this was IDed for sure I dont know) and a Parrot so what else could be going on?

as a result of these data I can't see a single reason for them being treated as species at the moment

so therefore, as for field ID......HA!

griffin · Feb 25, 2004

Hi Tristan,

It would be interesting to note the type of trees that the birds were in or in the local area. Although they say it is not 100% reliable I believe that Parrot Crossbills prefer Scots Pine trees in Scotland. This creates a kind of conundrum in that these ( Pines ) do not fail a crop as much as Spruce sp. in Fenno Scandanavia and expains why large nos. of Commons irrupt, and possibly explains why Parrot irruption is more sporadic.

Kielder strikes me as being a Forestry Comm. type affair ? and this would explain Common 'bills but Parrot or Scottish would be rare. Sounds like a Scottish one though as they are more catholic in food preference. They have been reported in Dum. and Galloway, but these reports are taken with some caution I believe.

Doesnt help you much I know !

Linz

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