Reverse and cross migration of Western Honey Buzzard Pernis apivorus at the Apuane Alps watch-site (Tuscany)

Abstract

The aim of this study is to analyse the migration flow of the Western Honey Buzzard Pernis apivorus observed on the western slopes of the Apuane Alps (Capriglia, Pietrasanta, Lucca, Tuscany). In spring, over a 12-day sample period from 9 to 20 May 2012-2014, a total of 738 individuals were recorded (148, 340, 250 respectively). Most Western Honey Buzzards observed (N = 466; 63%) had a reversed direction of spring migration, incoming from NW and heading SE. In autumn, over a 30-day period from 1 to 30 September 2012-2014, a total of 598 individuals were recorded (155, 111, 332 respectively). A proportion of the Western Honey Buzzards observed (N= 173; 29%) had a reversed direction of autumn migration, incoming from SE and heading NW. Autumn data suggest that mainly adults migrated towards NW, while mainly juveniles followed the innate autumn southbound direction. The particular behaviour of some Western Honey Buzzards heading NW and others heading SE creates a “cross migration” among the same species at the Apuane Alps watchsite, with individuals which possibly belong to different populations that cross their flyways, incoming from different directions and outgoing to different destinations at the same time. The regularly observed behaviour of the Western Honey Buzzards heading SE in spring and NW in autumn shows a spring and autumn reverse migration, adopted probably by a portion of the Central Italian population, which most likely performs a deviation from the main western European migration flyway.