First Genetic Evidence Confirming the Occurrence of the Siberian Chiffchaff Phylloscopus collybita tristis Blyth, 1843, in Italy

The Siberian Chiffchaff is a subspecies within the “Chiffchaff complex”, characterized by a typically pale greyish plumage and distinctive vocalizations, although reliable identification may still require genetic confirmation. In Italy, the taxon is considered fairly rare and poorly documented, with previous records based exclusively on identifications provided from registrations of the call or photos. This study provides the first genetic confirmation of the occurrence of Siberian Chiffchaff in Italy through molecular analysis of an individual captured at the Longola ringing station (Poggiomarino, Naples) on 21 December 2025. DNA was extracted from a feather sample. A fragment of NADH dehydrogenase 2 mitochondrial gene and a fragment of Aconitase 1 intron 9 were amplified and sequenced. A phylogenetic dataset including representatives of all taxa within the “Chiffchaff complex” was assembled and analyzed using maximum likelihood methods. The resulting phylogeny placed the sampled individual within the P. c. tristis clade. Morphological examination of photographic material also supported the identification, highlighting the almost complete absence of green and yellow tones in the plumage. Among 452 Chiffchaffs captured at the study site, between October 2025 and March 2026, only one individual showed potentially compatible tristis-like phenotypic traits and was genetically confirmed.