Age-related timing of Short-toed Snake Eagle Circaetus gallicus migration along detoured and direct flyways. Issue 1 (2nd January 2017)

• Record Type: Journal Article
• Authors: Agostini, Nicolantonio; Baghino, Luca; Vansteelant, Wouter M.G.; Panuccio, Michele
• Is Part Of: Bird study. Volume 64:Issue 1(2017)
• Page Start: 37
• Page End: 44
• Publication Date: 2017-01-02
• Subjects: Birds -- Ecology -- Great Britain -- Periodicals; Birds -- Conservation -- Great Britain -- Periodicals; Birds -- Ecology -- Periodicals; Birds -- Conservation -- Periodicals; Birds -- Great Britain -- Periodicals; Birds -- Geographical distribution -- Periodicals; Birds -- Counting -- Periodicals; 598.170941
• DOI: 10.1080/00063657.2016.1264362
• Languages: English
• ISSNs: 0006-3657

Abstract

ABSTRACT: Capsule: Juvenile Short-toed Snake Eagles Circaetus gallicus hatching in the peripheral populations of Greece and Italy have limited opportunities for social learning of migration routes compared to those hatched elsewhere. Aims: To test the prediction that there would be a higher degree of migration synchrony between adult and juvenile Short-toed Snake Eagles originating from peripheral populations and using an extremely detoured flyway, when compared to other populations using a direct overland flyway. Methods: We use linear regression models to compare seasonal changes in the age distribution of migrating Short-toed Snake Eagles counted at two migration watch-sites in Italy (Arenzano) and Georgia (Batumi), along a detoured and a direct flyway, respectively. Results: Juveniles migrated a few days later than adults at both sites and the age ratios recorded at these two sites was similar. The daily proportion of juveniles increased along a similar slope during the migration season, thus showing a similar degree of synchrony between the age classes on both flyways. Conclusions: Contrary to our hypothesis, juvenile and adult migration is not more synchronized in peripheral populations using a detoured flyway compared to a core population using a direct migration flyway. Our results suggest that juveniles do not learn detours to complete trans-Mediterranean migration from their parents, but from other elders.