Male Purple-Crowned Fairy-Wrens (image) University of Melbourne Caption Male purple-crowned fairy-wrens sing trill songs in response to predator calls. They seem to take advantage of the attention attracted by predator calls, and sing their advertising songs when females are paying most attention. Credit Michelle L Hall Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.