Learning to sing like your neighbours: a long-term field study in the black redstart Phoenicurus ochruros
Résumé
Both humans and oscine songbirds learn their vocalizations by imitating mainly conspecific adults. In oscine songbirds, song learning programs are diverse; for example, some species can only learn during the first months before their songs crystalize while others can learn new songs throughout their lives. We investigated the lifetime evolution of male song repertoires in a migratory population of a territorial songbird, the black redstart, by recording colour-ringed individuals during eight consecutive breeding seasons (2015-2022). Our study population is situated in a French mountain village of the Forez mountains with scattered patches of human buildings which constitute the breeding habitat of the black redstarts. We previously described the existence of micro-dialects between the different male clusters of 2-8 territorial birds. Males (n=24) were recorded at their arrival from migration for their first breeding season as well as during the following years. Most males sang the full local dialect upon arrival and those individuals kept their song repertoires stable throughout their lifetime (2 to 8 years). Those who shared only a few or no songs with their neighbours when they first established breeding territories (9/24), changed their repertoires mostly at their arrival for their second breeding season. Three types of modifications were observed: 1) addition of shared songs (4 individuals), 2) selective attrition of unshared songs (6 individuals) and 3) syllable structure adjustments (3 individuals). All the repertoire changes resulted in an increase in song sharing with neighbours. Our results suggest that black redstarts are able to adapt their song repertoires to their social environment.