Well, it's actually an opera. There are singers and musicians placed in different locations around the lake. The composition was intended to be performed at sunrise. The wolves actually chime in near the end of the recording, I guess they wanted to get their two cents in. Here's a little blurb I found about it: "remember the work for radio Wolf Music (1997), by R. Murray Schafer, in which a group of musicians spend a whole day playing his scores in a Canadian nature reserve - the manipulation lies in the way the microphones are set up and specific venues chosen. In short, it is a kind of sound mirage"

Good link Jim! Have you heard the piece before??