Tony mentioned strange bird behavior in his post:
 
http://www.fivedoves.com/letters/june2005/tony63.htm
 
   Others have mentioned strange animal behavior before.
We have a dog family of four yellow mixed labs. Within the last few weeks they have begun doing something very strange that they have never done before. Whenever they hear a siren they immediately start howling together, heads in the air, like a pack of coyotes or wolves.
    It is kind of funny to watch them, but I'm sure the neighbors are not amused, as sometimes it happens during the middle of the night. I first thought of it as doggy singing, but my husband says it is crying, as it is a very mournful sound. Perhaps they have some kind of sense that lets them know when a siren is sounding it is always in response to a "mournful" situation.