I wonder if there is possible benefit in doing spectral analyses of recofdings of bird calls and other animal sounds. Chemists use spectral analysis very effectively, i.e. they pass the light through a prism or other refracting device to identify the different frequencies present. Although I doubt that there are precise frequencies that we could associate with different species, the patterns might be distincitve.
Very different spectral patterns can give the same appearance of colour -- that is how colour printing works, by just mixing together various combinations of three pure colours. I suspect that sounds which we perceive as identical could have very different mixtures of frequencies, and these could be used for identification. Bill Silvert ----- Original Message ----- From: "stan moore" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, June 21, 2007 11:03 PM Subject: Re: ivory-bills and use of sound > Chris -- > > Think submarine warfare. Essentially all detections are by sound of both > enemy and friend and much is at stake. In wartime, would a submarine > commander launch a strike against an object which is not identified with > an > adequate level of certainty? I don't think so, but yes, I am sure it is > often possible and will be increasingly justifiable to use sound-based > data > to make reliable detections of biological phenomena. To get there, we > need > adeqaute baseline data, validation, and experience in utilization plus > resolving uncertainties one way or another. The ivory-bill situation is > pretty unique for obvious reasons but many ornithologists, for instance, > could readily detect a song sparrow by sound only. > > This reminds me of a story I heard about a friend who is an ecologist in > Southern California. He was leading a crew to the nest of a golden eagle > and someone heard sounds that were interpreted to be calls of a mountain > lion. The senior ecologist cupped his hands and duplicated the sounds, > and > the "lion" continued to respond. But someone noticed that when certain > overhead wires suspended from a transmission tower blew in the breeze, the > sound occurred and the revelation became soon apparent that there was no > local mountain lion involved. Of course, this problem occurs relentlessly > in the visual identifcation mode as well. Many raptorphiles have reported > seeing raptors on poles that turned out to be ceramic insulators and not > rough-legs or gyrfalcons.
