A compilation of common crossbill Loxia curvirostraL., 1758 ring-recovery data from the Iberian Peninsula and other European regions

In November 2021, a female common crossbill ringed in Switzerland was found in the Sistema Central mountain range, within the administrative border of the Community of Madrid (Spain). This is an unusal record due to the lack of data on irruptions of this species from central or northern Europe in the centre of the Iberian Peninsula. In this study, we have compiled all the existing common crossbill ring-recovery data from Iberia and other European regions. Our results show that common crossbill populations in the Iberian Peninsula are mainly sedentary, with limited movements across the different pine forest masses in search of food. In contrast, northern European common crossbill populations develop long distance migratory movements that may involve a large number of individuals following a NE-SW axis that, in an irregular manner and depending on the year, can arrive in the Iberian Peninsula in mid-August or September, where they may remain for several years before returning to their places of origin. In the Iberian Peninsula, these crossbills seem to use the pine species available as a trophic resource according to their ecological speciation, including species not present in their regions of origin.