The ads for ultrasonic bird and rodent (and even insect) control devices appear everywhere, yet, try as I might, I can't find a single scientific, controlled study on the effectiveness of these devices. A number of people have told me that the devices work for a few weeks or months, until the intended victims grow accustomed to the sound, and then they are no longer effective. If anyone out there in Museum-L land has a reference of a study where ultrasonic devices were show to be effective or ineffective, please post it. It would be such a nice world if only these devices would really work! John Simmons Collections Manager Museum of Natural History University of Kansas