Birds that live in areas where the weather is variable also havea much more diverse repertoire of songsthan those that live in environments with stable conditions. These are the surprising conclusions of a study published in the journalBiology Letters.
The researchers, from the Australian National University and NESCent (USA) recorded the songs ofmore than 400 male birds belonging to 44species present in North America, including orioles, blackbirds, warblers, sparrows, goldfinches, chickadees, and thrushes. They then used a computer application to convert each recording – a mix of chirps, trills and whistles – into a sound graph on which characteristics such as duration and number of notes could be measured. By combining these variables with data fromtemperature, precipitation, habitat and latitudeOf the areas where each bird lived, the scientists observed that the ‘artists’ living in areas with the most drastic seasonal changes had the most varied repertoires.
The results do not appear to be a mere coincidence. “Sound is not transmitted in the same way through all types of vegetation,” explains Clinton Francis, one of the authors. “When the birds arrive in the area where they spend the spring, it is possible that the trees do not have leaves. And, just a few weeks later, the leaves will begin to sprout and the acoustic conditions will change completely,” he adds. “The most versatile birds in their songshave a better chance of being heardin the different acoustic environments in which they move throughout the year “, adds Iliana Medina, another of the authors.
Furthermore, the scientists also found that species with higherdifferences in color between males and femalesThey also had more varied repertoires, so it seems that environmental variability is not the only one that determines the musical diversity of birds, according to the authors of the research.
