Can birds understand the songs of other species?
Young songbirds learn to sing by listening to their parents and mimicking them, much like the babbling of human babies. By the time they leave the nest, they have these songs memorised, and can use them to find and select an appropriate mate. Some birds are able to learn songs of other species, says Wheatcroft, a zoologist at Stockholm University in Sweden. Mimics such as lyrebirds, for example, specialise in copying other species (as well as other sounds in their environment). But even in non-mimics, birds can and do learn each other’s songs. “You can have different species coming into contact, and when they co-occur, one species can learn the other one’s song, or vice versa,” he says. For example, zebra finches and Bengalese finches are distinct species. In experiments that place zebra finch chicks with Bengalese foster parents, the young birds are able to learn their neighbours’ song – but not perfectly, and probably not to the degree where they’d manage to attract a Bengalese finch. In this way, songs are thought to function as an important barrier between species to stop interbreeding and avoid the population potentially collapsing. Wheatcroft’s interest lies in how and why the preference for species-specific songs has evolved, and determining how genes and experience determine the songs that are sung. “The ecologically relevant thing is what happens when species co-occur in the wild, because rarely in the wild will one species rear chicks from another,” he notes. Through the SongNeuroGen project, which was funded by the European Research Council(opens in new window), Wheatcroft and his colleagues explored how species recognition arises between the collared flycatcher and the pied flycatcher. The team showed that throughout Europe, pied flycatcher nestlings as young as 12 days can discriminate their group’s calls from the songs of collared flycatchers. The research also found evidence of genetic differences between populations that work to ‘tune’ birds towards their own songs. So while they can attempt melodies from related species, birds tend to have an innate reticence to learning new songs. “You might think a male that sings something novel is sexy, more attractive,” adds Wheatcroft, “but from most of the examples that we know of, conservative is what plays best.” Click here to find out more about David Wheatcroft’s research: Learning to speak the right language: how juvenile birds learn what to sing
