Birds decide when to call and not to call

Hi all, I saw this on the ABC site re birds choosing when to call in relation to potential threats. Thought some others may find it interesting to read. http://tinyurl.com/mygyxq2 Regards Carla =============================== To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line) to: birding-aus-request@vicnet.net.au http://birding-aus.org ===============================