Plumages are similar to those of the Common and Parrot Crossbills, red in the male and greenish in the female. This species differs in voice, and also in biometrics and structure, being intermediate between the other two. Scottish Crossbill Bird shares a preference for pine trees with the Parrot Crossbill, and has a similar bill, but without the pronounced 'S'-shaped curve on the lower mandible. The bill appears blunter and more massive than the Common's and is nearly as deep as it is long, with a stronger curve to the culmen and with the base of the culmen relatively less curved. Scottish Crossbill Bird is broader headed than the Common, and larger and bulkier overall. Particular care must be exercised when assigning identity to crossbills within the breeding range of this species, as not only Parrot Crossbill can occur but at least three 'cryptic' forms of Common Crossbill have been recorded!
Scottish Crossbill Bird is restricted to tracts of mature Scots pine in the Scottish Highlands, particularly Strathspey and Deeside. Scottish Crossbill Bird is dispersive, but difficulties in identification mean that it is under-recorded and overlooked outside its core breeding area.
The calls of Scottish Crossbill Bird, like the bird itself, are intermediate between those of the Common and Parrot Crossbills. The flight call is a simple "chp chp chp", more similar to the Parrot Crossbill in its plainness but slightly higher pitched, and also without the 'clip' quality of the Common. The diagnostic call is the excitement call, a deep "chlupp chlupp", like two notes, one on top of the other. The song follows a similar pattern, perhaps with shorter and less complex phrases, and with longer pauses between segments, as in "dzhip dzhip dzhip p'chuwi p'chuwi... tchptchp.. pt'jhirri jhirri tchrrr tchrrrr".