Four decades later: The highly conserved repertoire of song types in chaffinch (Fringilla coelebs)

The long-term stability of culturally transmitted traits like bird song has attracted much attention from researchers; however, it remains insufficiently studied up to the present time. This study investigates, by using spectrographic analysis, whether the repertoire of song types recorded at the same locality is persistent at short terms (of four years) and at long terms (of 38 years) in a migratory European continental population of chaffinches. The population song type repertoires recorded in 1978 and 1982 were only slightly different, thus indicating the high repertoire persistence within a few years. There were more differences between repertoires recorded in 1982 and 2020. In total, eight of the 29 song types (28 %) identified in 1982 were not found in 2020, and 5 of the 26 song types (19 %) discovered in 2020 were completely new compared to 1982. All the other song types recorded in 2020 were similar to those recorded in 1982. The frequency of use of these song types in 1982 and 2020 was also similar. By 2020, mainly those song types had disappeared from the population repertoire, which in 1982 were performed by a limited number of males. These data suggest a high long-term persistence of repertoire of song types in male song of a migratory continental population. This long-term stability of the population repertoire was maintained despite significant changes in the habitat structure caused by a massive expansion of bark beetles in 2010-2014.