Primordial music

On June 21 I performed my annual summer solstice ritual, participating in the North American Breeding Bird Survey This year I was assisted by my father, who drove the car and counted passing vehicles, allowing me to concentrate on gathering bird data.

When we left the cottage at 4:26 a.m., a faint blush had begun to spread across the northeastern horizon which faces our property. But the woods was still silent, except for a muted murmur of bullfrogs along the far shore of the lake. Apparently they had gathered in one of the marshy bays to breed.

By the time we reached the starting point of our 40 kilometer trek, the woods had come alive, shimmering with primordial music: from the giant white pine above the gas station in Dwight came the bell-like trill of a chipping sparrow. In the rich deciduous woods near the next few stop points, the chorus of warblers, thrushes and vireos was so thick and their voices so numerous it took all my concentration to distinguish one from another and discern its owner.

It takes four or five hours to drive the route, stopping every 0.8 kilometers, getting out for three minutes each time and standing quietly, counting every species of bird you see or hear. There are 50 stops, each carefully recorded so they can be precisely repeated each year. Volunteers complete these same surveys wherever there are passable roads in North America, some day between late May and early July. They must begin a half hour before sunrise, because early morning is the time when birds are most active. The data provides only an index, because many breeding bird species are more difficult to detect than others, but it gives a good measure of avian biodiversity in each area.

This isn't an easy birdwatching expedition. Songs are far more numerous than sightings, and all must be identified. In late June in Central Ontario, with the trees in full foliage, few birds can be seen, but their voices are everywhere, and are distinctive to each species, though some are more difficult to distinguish than others.

My father's company made this phenomenon even more pronounced to me. His hearing isn't bad, but he has lost his perception of the higher registers. For him, the woods was largely silent.

Birds evolved their elaborate voices tens of millions of years ago. They are capable of such diverse sounds because of a specialized voice box. Just as the human pharynx allows us to modulate our voices for complex speech, birds have a highly developed voice region at the bottom of their larynx, called a syrinx. The complexity of this organ allows birds to produce more than one note at once. These undertones or overtones are most beautifully evident in those accomplished singers of the Northeastern forests, the thrushes. Five of these species could be heard along my route, including the American robin, the veery, and the wood, hermit and Swainson's thrushes.

Go To Page: 1 2