A new study, published in the latest issue of the journal Science Advances, revealed how a Siberian jay - a tiny corvid with a widespread distribution within the coniferous forests in North Eurasia - can use bird lies to trick other flocks into leaving a territory, so that the interlopers can move in and nick their food.
But it seems that other Siberian jays are also wise to this ruse. The research has found that breeding members of a family group can distinguish between the warning cries of their own flock, and the warning cries of would-be trespassers.
Siberian jays are quite fascinating birds. They mate for life and tend to live in small flocks of fewer than 10 members, with one dominant breeding pair.
Within this group, they have been found to exhibit nepotistic alarm calling: when danger is nearby in the form of a predator, they sound a cry that will alert family members, telling them to scarper. However, some neighbors from other flocks use deceptive warning cries even when there is no serious danger, so they can steal food that the jays put away, without having to resort to physical altercation.
To observe this in action, ornithologist Filipe Cunha of the University of Zurich in Switzerland, and evolutionary biologist Michael Griesser of the University of Konstanz in Germany designed an experiment for wild jays in their natural habitat.
They set up a feeder with a speaker nearby, and placed a lump of pig fat to lure in foraging birds, along with a video camera set-up to record the birds' actions.
Through the speaker, the scientists played warning calls from other Siberian jays - those that were former members of the bird's own flock, those from flocks in neighboring territories, and those from birds the target bird had never encountered before.
"Our results demonstrate that Siberian jays respond differently to playbacks of warning calls depending on the social relationship to the caller. Breeders immediately escape to safety when exposed to warning calls from former group members but not when exposed to warning calls from neighbors or unknown breeders. Siberian jays are familiar with all their neighbors and encounter them on a daily basis," the researchers wrote in a report posted on the Science Alert website.
"Moreover, familiarity between the neighbors that meet daily alone does not breed trust. Siberian jays trust only warning calls of former cooperation partners," they noted.
