The crossbills are characterised by the mandibles crossing at their tips, which gives the group its English name. They are specialist feeders on conifer cones, particularly the various spruce species but also some populations (different species?) in Douglas-fir and various pine species, and the unusual bill shape is an adaptation to assist the extraction of the seeds from the cone.
Adult males tend to be red or orange in colour, and females green or yellow, but there is much variation.
Plumage distinctions from Parrot and Scottish Crossbills are negligible. The head and bill are smaller than in either of the other species. Care is needed to identify this species. The glip or chup call is probably the best indicator.