Alarm calls of scrubwrens were played to wrens in Canberra and Macquarie. Only fairy-wrens in Canberra (where there are scrubwrens) fled for cover. Fairy wrens in Macquarie (where there are no scrubwrens) did not respond. In another test, recordings of honeyeaters were also played to fairy-wrens. The fairy-wrens sought cover. They had learned the honeyeater calls.
Professor Gisela Kaplan believes that the behavior is not totally due to learning. She believes that the brains of birds are preprogrammed to act when they hear alarms of other birds. Tests done on magpies showed that they found cover only if the alarm calls of other birds were played close to them.