We've been completing quite a few NWPodcasts lately - its been a cold Feb and March so far, and the fish really haven't started biting so we are making hay while we can ;-) This podcast is some of our exploration of ultrasonic sound. You've probably heard of bat detectors - these simple circuits take untrasound that we humans can't hear, and shift them down into frequencies we can hear. It is fun listening to bats, insects, scratched glass, and even running water... but what really gets us excited is listening to elk, deer, rabbits, and coyotes!
For years I've been convinced that elk and coyotes can hear frequencies well above what we hear. Most of coyote prey makes these sounds, and dogs can here them, so it only makes sense! My favorite part of hunting is vocalization - calling to elk or coyotes. What if our calls make sounds that we can't here, that distinguish us from a "real" animal?
Recently scientists have been listening to trees, to see if their ultrasonic noises are attracting pine beetles and other parasites. Very cool!
In this podcast, we'll demonstrate some of the sounds in the ultrasonic frequency range (20kHz to 100kHz), and even demonstrate a coyote and elk call with the ultrasonic noise they make. We've started "upgrading" our equipment too, so that later this summer we can measure and record animals in the wild to profile their frequency ranges. This is a fun one with the kids, and interesting for you hunters out there, too.
A very good, basic detector with schematic and even build instructions can be found here: http://home.earthlink.net/~bat-detector/BatDetector.html This is something the kids will really enjoy when they explore new sounds. When the kids start bugging eachother - I assign them to go and find 5 new 'sounds' we've never heard before, and it is great what new things they discover! More on that in a future podcast as well ;-)
Here's the podcast - it is ~8MB in size, and about 10 minutes long:http://nwpodcast.comuf.com/nw106_ultrasonic_elk.mp3