Relationship between biometry and migration time among Blackcaps (Sylvia atricapilla) in central Italy
Gustin M., Pizzari T., Capizzi D.
The relationship between morphometric parameters as well as fat score and migration time was analysed in Blackcaps (Sylvia atricapilla) during the pre-breeding migration across Italy. After controlling for body size age- and sex-related significant differences in wing length, wing shape and fat score were found, with birds passing towards the end of the season having longer and more pointed wings as well being fatter. Body size also explained part of the variation in morphometry. We suggest that as the migrating season progresses Blackcaps are more likely to be directed to breeding quarters increasingly further away from the study area, possibly in northern and eastern Europe. These results provide evidence that different populations of Blackcaps, which appear to be statistically distinguishable on the basis of morphometric and fat score variation, intersect Italy during migration.