A macrorhynchos-like Eurasian Nutcracker (Nucifraga caryocatactes) in the Dolomites with a very abraded ring: an aged immigrant, or a locally born bird?

摘要

The origin of the ringed bird, photographed at Passo Gardena on 28 July 2016, remains unknown. However, considering that 1) irruptions of the macrorhynchos subspecies into the region have not occurred for years compatible with the degree of abrasion of the ring; 2) dispersed macrorhynchos individuals rarely survive for long periods outside their population range; 3) intermediate morphological traits between macrorhynchos and nominate caryocatactes appear in the area; and 4) the nominate subspecies may be derived, the possibility of a locally born representative of a hybrid population, or a bird with ancestral traits, should be considered for future studies.