Ron Summers / February 2020 – vol. 113, issue 3, pp 152–164 Ron SummersDiscussionThis paper refines our understanding of the relationships between crossbill size (species) and their calls, noting uncertainties and apparent changes in calls. Compared with an earlier study (Summers et al. 2002), the increased sample size of recordings of birds of known size confirmed that some of the flight calls (1 and 4) and excitement calls (A, B, C and E) are specie... This article is only available to registered users.To read more, please log in or purchase a subscription.