Data and R code from: Fin whale song evolution in the North Atlantic

Animal songs can change within and between populations as the result of different evolutionary processes. When these processes include cultural transmission, the social learning of information or behaviours from conspecifics, songs can undergo rapid evolutions because cultural novelties can emerge more frequently than genetic mutations. Understanding these song variations over large temporal and spatial scales can provide insights into the patterns, drivers and limits of song evolution that can ultimately inform on the species’ capacity to adapt to rapidly changing acoustic environments.

In this study, we analysed changes in fin whale (Balaenoptera physalus) songs recorded over two decades (1999–2020) across the central and eastern North Atlantic Ocean. We document a rapid replacement of song INIs (inter-note intervals) over just four singing seasons (2000/2001–2004/2005) in the southeast location of the Oceanic Northeast Atlantic (ONA) region, that co-occurred with hybrid songs (with both INIs). During the transition in song INIs (2002/2003) we show a clear geographic gradient in the occurrence of different song INIs in the whole ONA region. We also found gradual changes in song INIs (Figure 3A) and 20-Hz note (Figure 3B) and HF note (Figure 3C) peak frequencies over more than a decade with fin whales adopting song changes. These results provide evidence of vocal learning in fin whales and reveal patterns of song evolution that raise questions on the limits of song variation in this species.

Methods
The dataset was collected by underwater autonomous recorders from 15 regions of the Central and Eastern North Atlantic from 1999 to 2020. Fin whale songs were selected according to the criteria specified in the paper's methods (Song selection criteria) and processed using Raven Pro 1.5 Software. This software measured internote intervals and peak frequencies of the 20-Hz note and HF note for each song analysed. These measurements are found in the datasets provided here and sorted by day (or song, as one song was analysed per day), region, location and year.