BIRDS MAKE FRIENDS WITH OTHER SPECIES BY SINGING SONGS
Songbirds can recognise familiar members of their own species by each individual’s unique song. Indeed, studies have also shown that different species of birds recognise and cooperate with each other. But a study recently carried out in Australia suggests that these links may be between specific birds rather than the species in general.
A team from the University of Chicago and the University of Nebraska investigated two species of fairy wrens, variegated and splendid, and found that the birds can recognise particular individuals of the other species. Both species of wren are small, non-migratory songbirds that feed on insects, live in large family groups and breed at the same time of year. The breeding males of both species have striking blue feathers.
“Splendid and variegated fairy wrens are so similar in their habitat preferences and behaviour, we’d expect them to act as competitors,” said Christina Masco, a graduate student from the University of Chicago who coauthored the study. “Instead, we’ve found stable, positive relationships between individuals of the two species.”
The first clue came when the researchers played a recorded vocalisation of a wren from one species and noticed that birds from the other species would respond to the call and fly in to investigate. Subsequent experiments involved playing vocalisations from familiar and unfamiliar birds to simulate an intrusion into the wrens’ territory.
Both splendid and variegated fairy wrens were able to recognise the songs of birds from either species that shared their territory and would respond non-aggressively. Songs of birds from entirely different species drew similar responses. But dominant males of both species responded aggressively to unfamiliar songs belonging to splendid and variegated wrens from other territories.
By forming and keeping these associations with another species, it’s thought that the fairy wrens can better defend their nests from predators and their territories from rivals.
“WE’VE FOUND STABLE, POSITIVE RELATIONSHIPS BETWEEN INDIVIDUALS OF THE TWO SPECIES”
Splendid fairy wren males shimmer with bright blue feathers