The plumage is similar to that of the Common Crossbill, being red in the Parrot Crossbill Bird (male) and green in the female, but this is the largest of the crossbills, with a bigger head and a thicker, more bull-necked profile than the others. Apart from the subtle differences in the voice, close study of the bill should indicate this species. Parrot Crossbill Bird is large and heavy, as deep as it is long, and with a deep lower mandible that has a deeply curving lower edge forming an'S' shape, a strongly arched culmen and shorter extended tips to the bill. This gives it a front-heavy appearance, enhanced by a flatter forehead, and it is a larger and bulkier bird overall.
Parrot Crossbill Bird is resident but dispersive and occasionally irruptive, although less frequently than Common Crossbill. Parrot Crossbill Bird breeds in Scandinavia and eastwards, and is a scarce visitor to much of Britain, although it has recently been detected as being present and occasionally breeding in the Scottish Highlands. It favours coniferous forest, particularly of Scots Pine, and during irruptions may also occur in spruces. Irruptive birds may stay to breed in the areas that they reach.
Parrot Crossbill Bird is quite vocal, the calls and song being very similar to those of the Common Crossbill but discernible by a practised ear. The flight calls are deeper, harder and less ringing, without the 'clip' quality that Common Crossbill has, as in "chop chop chop" or "djup djup". The excitement calls are similarly rather deep, but softer and rather percussive, sounding more conversational, such as "chhp chhp chhp". The song of Parrot Crossbill Bird is rather better defined and, although in a similar pattern to Common Crossbill, sounds more emphatic - with loud, harsh, slightly upward-inflected metallic trills, and sometimes more fluty whistles reminiscent of a Tree Pipit, such as "dzhrrr'eh dzhrrr'eh dzhrrr'eh chp'chp'chp' tsiri tsiri i'chup i'chupzhr'p zhr'p izhp'izhp bt'bt'bt..." etc.