Crossbill calls

I am close to being tone deaf which results in an atrocious singing voice and also causes me to be oblivious to many of the subtleties of the Norwegian language much to my family’s amusement. In birding terms it means that I struggle to differentiate between some similar calls. On Friday I heard Common (grankorsnebb) and Two-barred Crossbill (båndkorsnebb) calling simultaneously and found the differences to be slight. Here I have compared the contact calls of both species.