Hearing is believing: Birds learn fear.

Although it is known that animals attend to the vocalizations of others (referred to as eavesdropping), what has been missing, or at least left experimentally unproven, until now is whether animals can learn new associations between a signal and a threat. Here Magrath and colleagues (Current Biology, 25(15), 2047-2050, 2015) have for the first time conducted a field experiment that demonstrates just this: superb fairy-wrens learned to associate a novel vocalization with a predator.