Bird songs and soundscapes

• by Michael Morris, Mount Revelstoke and Glacier National Parks
• May 28, 2003

Nothing heralds the arrival of spring quite like the sounds of birds and I try to keep up with the stream of newly returned bird species to Columbia Mountains. Week by week, the morning soundscape grows in volume and variety, serving up the audio jewels we’ve missed all winter.

Bird watchers may be known for the binoculars hanging around their necks, but due to the dense vegetation of this region, I prefer to keep track of the bird world more by listening than by looking. Bird sounds distinguish species better than any other trait.

Increasing day length stimulates the production of the hormones that drive male birds to sing. They sing through the spring and early summer to establish territories and to attract mates. A female bird evaluates a male bird’s desirability as a partner by a careful examination of his vigour, usually expressed as bright plumage or the quality of his song. A male must be a successful forager to have enough energy to grow bright new feathers or to sing constantly during the spring courtship period. Brightly feathered male birds use appearance to intimidate rivals or catch the attention of females. In contrast, the muted plumage of some female birds seems intended for camouflage. Bright feathers or singing must make males much more susceptible to predation.

Soundscapes

Sound is so much a part of our world that we often ignore it. Computer fans, furnaces, refrigerators, fluorescent lights, passing vehicles, train whistles, lawnmowers, chain saws, and so many other mechanical sources of noise have conditioned us to tune out. In those increasingly rare places quiet enough to hear natural sounds, many of us lack the skill to know just what it is we are hearing. Park visitors frequently ask us to identify a bird song they have heard but we have difficulty understanding their description of the sound. In comparison to the range of words we have to describe what we see, we lack vocabulary to discuss what we hear. Test your own skill at describing a particular bird song to someone else.

To help us out, the Friends of Mount Revelstoke and Glacier sponsored the production of a CD, “Discovering Birds and Their Songs in Mount Revelstoke and Glacier National Parks.” It points listeners to where and when to hear the key birds of our wetlands and forests, using local recordings. Paying attention to birds, while interesting in itself, is but half the treat. Tuning into the natural soundscape opens us to all that peeps, squeaks, hums, buzzes and crackles in the Columbia Mountains.

Anyone with patience and a moderately priced cassette deck can collect sounds. Minidisk recorders work even better. However, the keys to the creation of a good sound clip are a quality microphone and a quiet background. Of the many styles of microphones, the most common for this purpose are: the shotgun mic, the kind used by TV news reporters, which is very directional and aimed at the sound source; and the omni-directional mic, which gathers sound in all directions equally. An omni-directional mic mounted in a parabolic dish can isolate sound even better than a directional mic. Recordings are played back into a computer by way of a simple cable for editing. What used to require an elaborate sound-editing studio can now be handled with inexpensive computer software.

Click to hear Michael’s recordings:

• Black-capped Chickadee (25 KB MP3 file)
  
• Swainson’s Thrush (76 KB MP3 file)