Elmberg, J / August 1991 – vol. 84, issue 8, pp 344–344 Flight calls of Two-barred Crossbill .Two-barred Crossbill Loxia leucoptera has three main flight calls which are, in the vast majority of field situations, clearly distinct from those of other crossbills. Crossbill L. curvirostra and Parrot Crossbill L. pytyopsittacus possess a wide, partly overlapping spectrum of flight calls, and separating these species on call is frequently problematic. Cross... This article is only available to registered users.To read more, please log in or purchase a subscription.