![]() Here we tested whether altruistic responses to calls for help vary across the distinct social levels of the society, akin to food sharing among hunter-gatherers, but with much higher stakes. ![]() This distracts the predator, and this "altruistic distraction display" places the bird that performs it at high risk. They may also use a distraction tactic called a "rodent-run." To do this, birds approach the threat to within striking range, assume a hunched posture, and scurry back and forth like a mouse. Other wrens commonly respond to such calls and try to help, for example by approaching the predator and giving alarm calls. While we are attaching their bands, we recorded any birds that gave distress calls, distinctive calls that individuals use to seek help when they're in imminent danger, for example from a predator. To make it possible to track those complex relationships, we attached different-colored leg bands to superb fairy wrens in our study population so we could recognize all individuals through binoculars. As a result, these birds develop social relationships of varying levels of intensity. Superb fairy wrens live in multilevel societies in which breeding groups-between two and six birds-represent the lowest social level, with tight social bonds among individuals.ĭuring the non-breeding season, neighboring breeding groups associate closely with a few other breeding groups, and these "supergroups" then associate to form communities (the highest social level). ![]() Living together means helping each other out In our research, published March 9 in Current Biology, we tested this hypothesis in a wild population of superb fairy wrens, a familiar little songbird across southeastern Australia's parks and gardens. One hypothesis, based on observations of two populations of contemporary hunter-gatherer people, is that living in a multilevel society allows people to simultaneously have different types (levels) of cooperative relationships. In fact, it's still common among many hunter-gatherer societies around the world.Įven though multilevel societies are documented across the animal world, it's not entirely clear what their benefits are. Such a social structure, which has been described in some primates, whales, elephants and more recently in birds, has likely characterized much of human evolution. At each level, the relationships between these social units (individuals, families, clans and tribes) are stable and predictable.
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