The Parrot Crossbill
The largest red crossbills live in Scandinavia and western Russia. There are no known plumage differences between these and smaller forms (Loxia "curvirostra") with which they coexist. Most authors have considered these largest crossbills a separate speciesLoxia pityopsittacus with no subspecies. This is like the situation in Scotland where large-billed Scottish crossbills breed in the same forests as "common" crossbills.
Little is known regarding the comparative behavior or biology of these or other European crossbills. The calls have not been described or compared to morphology, therefore it is not known whether all birds currently lumped under the name "parrot crossbill" represent a single evolutionary unit.
