Crossbills

Now that Redpolls have been lumped into one species I think it is time to do the same with Crossbills. Are Common Crossbill, Scottish Crossbill and Parrot Crossbill really different species or are they just different forms along a clinal range where dominant food source is the determining factor? My memory of reading what the Sound Approach wrote is that Common Crossbill contains so many distinct populations with different calls and bill sizes that they could just as easily be considered different species. Scottish Crossbill has always been a farce (don’t they go “missing” in some years and then turn up again with a slightly different call?) that I think was driven by Britain’s desire to have an endemic species but now that Red Grouse has been split from Willow Grouse then Britain has its symbolic endemic so Scottish Crossbill can be allowed to fade away. Parrot Crossbill at the extreme end does look and sounds very different from the opposite extreme of Common Crossbill but there are many, many birds that are somewhere in between and you (I) really struggle to put a label on them other than “crossbill”.

This last week I have seen a nice variety of crossbills that brought back my dislike of the species group. At the weekend we had some crossbills in nice mature pine (as opposed to spruce) forest. This would normally mean that they are Parrots and in Norway Parrots are called furukorsnebb (mean Pine Crossbill) whereas Common are grankorsnebb (meaning Spruce Crossbill). Looking at them in the binoculars it was not immediate what they were and neither were their calls particularly helpful one way or the other. Zooming in on photos I identified them as Parrots but definitely not the largest billed of their kind. Maybe they are a far better fit for Scottish? Is it not the case that crossbills develop bills to suit the food they are specialising in so a (sub)population that has good access to pine grows a larger bill than one that has access to spruce or larch?

Then on Monday I had classic Parrot and Common together (both in bill size and call) plus a bird that was somewhere in between.

male Parrot Crossbill (furukorsnebb) from Ringebu at the weekend

the bill does look huge on this one

the female looks classic Parrot but the male not quite

here they are looking good

but at this angle not so

And pictures from Monday closer to home:

this male is definitely not a Parrot although in the field that was my original conclusion

this pair with their smaller bills without parallel upper and lower mandibles are clearly Common Crossbills

the male of the same pair

a pair of Parrots Crossbills - large billed, bull necked classic birds

the male of the pair

this should be the same pair but the male is now looking quite different

this should be the same male who again looks different depending on angle

the female is the Parrots but the male is one of the Common Crossbills (possibly the first bird I have pictures and not from the pair)

here it is easier to see that the male is not a Parrot

the differences are perhaps easier to see here

This video has the two pairs and also the calls. The deeper call we hear most often is the Parrot and the higher pitched call is from the Common

here a still warm road kill juvenile Common Crossbill from Maridalen today. The bill looks to be fully developed