With the arrival of Spring I have been hearing lots of bird calls during my morning bike commute. There are lots of Robins, House Finches, and White-crowned Sparrows, but more exotic birds are also beginning to make themselves heard. In this past week I've heard the call of a Bewick Wren, Varied Thrush, Osprey, and a Bald Eagle.
I would like to be able to record individual bird calls, and once even attempted to build a sound amplifier that could be focused on an individual bird in the distance. The attempt was a miserable failure because it was difficult for me to shape anything into a thirty inch diameter parabolic shape.
Uncle Jim, a research physicist, helped me by demonstrating how a perfect parabolic shape could be generated using a spinning container of liquid. He told me I would need to figure out how to capture the shape. That's where it ended until recently when my friend Sasi, a chemical engineer, told me how to capture the shape of the liquid, and turn it into a solid that can be used as a template for building parabolic sound amplifiers.
What makes this especially important is that most recordings of bird calls don't sound anything like the bird you hear in your neighborhood. That's because they were recorded somewhere else, and birds have very different sounds depending on where they live.
For example, a White-crowned Sparrow in Western Washington doesn't sound anything like a White-crowned Sparrow that was recorded in Illinois. It is only vaguely similar to one that was recorded in Oregon. Even the distance between Tukwila and Bellevue is enough to make a noticeable difference in the call of these birds.
So maybe I need to begin making recordings of the
Bird Songs of Western Washington.
