Balloon Journeys over Minnesota and Nebraska
While studying avian nocturnal flight calls in the late 1980s, Bill Evans became fascinated in what birds hear as they are in migration flight over varied terrain. In an attempt to duplicate this experience, he began to carry out experiments using free-floating helium balloons with attached audio recording gear. Initial flights contained the audio recorder and a radio transmitter used for tracking the balloon. A specially designed timer and release mechanism on the balloon triggered the balloon to come down after a prescribed time aloft. Altitude of the flight was controlled by carefully determining the amount of lift the balloon had when it was released. Besides simulating the experience of what a bird might hear as it flies over miles of terrain, Bill was interested in the potential of using the technique for documenting wildlife populations in remote and difficult to census regions. In the late 1990s, GPS was added to the balloons allowing association of the recorded animal sounds with specific geographic locations. The technique was applied in a US Federally funded survey for a rare subspecies of the Willow Flycatcher in dense Salt Cedar stands along the Colorado River in 1999. The technique has potential for surveying songbird and amphibians in large inaccessible forest tracks in Canada and the United States.
This CD contains some of Bill's seminal recordings made over Minnesota's Superior National Forest and the sandhill region of western Nebraska in 1992. There are four soundtracks. The first is a 28 minute flight that floats over 8 miles of the Superior National Forest in northern Minnesota. This flight begins near ground level in the midst of the dawn chorus of songbirds. The balloon gradually ascends and picks up speed. Toward the end of the flight the balloon is over 1000-ft above ground and the sound of songbirds on the ground has faded into a cacaphonous mass. The second track is 7 minute cut from later in the same flight when the balloon is over 2000-ft above ground. The songbird chorus is now inaudible and only louder wildlife sounds such as calls from Common Ravens, the drumming of woodpeckers, and the howling of wolves can be heard. This is a subtle cut that needs careful listening. The volume on your stereo system may need to be turned up for this cut to full appreciate it. It is best appreciated with good headphones. The final two cuts are from a flight over the sandhills in western Nebraska. They feature many prairie and pothole species as well as coyote and a herd of cattle.
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