Birds have long had a very special place in my heart — as in most human hearts. Birds are magic, myth, fairy tale and the subject of intense scientific scrutiny. One of the startling ways in which birds have interacted with humans, of course, was the “canary in the coal mine” — the caged bird that accompanied a miner as he headed deep underground; the canary served as a sentinel, an early warning system of dangerous gases, like carbon monoxide or methane, leaking into the shaft. The bird died so the human could live.
Once again, birds are alerting us to the danger of poisons in our atmosphere. Only this time, we have not been paying attention, at our own peril. A recent study by the Biodiversity Research Institute in Maine noted that the same methyl mercury that causes neurological disorders in humans and especially children, also causes suffering among songbirds and bats. The study found dangerously high levels of mercury in several Northeastern songbirds, such as wood thrushes and blackbirds. Researchers note that birds in contaminated sites are three times as likely to abandon nests. Chicks are quieter, vocalizing less, not begging for food. Heartbreakingly, Zebra finches were unable to hit the high notes in their songs during mating rituals — and this affected their ability to reproduce.
The largest source of mercury pollution in our air? Coal-fired power plants. Exactly the polluters the new Mercury and Air Toxics Standards are meant to severely curtail — and which some in Washington, including Senator Inhofe, are loudly vowing to block. The news about birds serves as a double warning: human fetuses, infants and children are disproportionately affected by mercury contamination of our food. Mercury gets into our air and then drifts into water, where it converts to methylmercury and moves up the fish food chain. The largest emitters, apart from coal plants, are cement kilns, chlorine plants and facilities that recycle automobile scrap.
Songbird populations have been in steady decline in the U.S. That decline has already been linked to acid rain. Now we know that our rain is toxic, too. We are losing a critical population in our ecosystem — to say nothing of creatures who make our lives here that much more magical — and we are directly to blame for the suffering of those brilliant, antic, glorious, whistling and chirping companions. Yet another reason to fight for clean air.