13 June 2007

Silence of the Songbirds


Printable version

By Bridget Stutchbury

WALKER; 256 PAGES; $24.95

The dramatic decline in songbird populations is a crisis that's unfolding worldwide, writes York University Professor of biology Bridget Stutchbury. While this change may not at first appear as dangerous as global warming, the ozone hole, overpopulation, increasing pollution or massive deforestation, once again, birds -- like the canaries used long ago to alert miners of invisible, fatal underground gases where they worked -- have become universal biological indicators of rapidly worsening, urgent environmental troubles.
Some estimates set the songbird population loss during the past four decades alone at almost half. Why should we care? Because, Stutchbury explains, "Their jobs as pollinators, fruit-eaters, insect-eaters, scavengers, and nutrient recyclers will not get done, and this will disrupt ecosystems and affect everyone on the planet."

New World songbirds spend part of their year in Central and South America, then as autumn approaches there, they migrate north during April and May to breed in the Northern Hemisphere just when spring insect populations burgeon and plants bloom. The fewer the birds, however, the fewer the insects they and their young consume, necessitating increased human dependence on pesticides, whose long-term toxic effects are themselves a major cause for concern.

The same is true for bird species working as pollinators or distributors of the seeds they eat: Fewer birds mean fewer plants and less diversity, which -- alongside rapacious, unsustainable human practices -- mean smaller, ever more fragmented forests, less rain and more erosion, all contributing to a cycle of chronic depletion.

Songbirds, Stutchbury demonstrates chapter by chapter, "are the unsung heroes of our modern world." Everyone knows we would have precious little food without bees or worms, but research is now beginning to reveal how many crucial roles songbirds play in the interlocking puzzle that supports the health of the natural world, too.

Bird counts begun in the 1960s provided a baseline. No census will ever be entirely accurate, Stutchbury writes, due to the huge numbers of birds and the enormous distances they travel annually. And it's because of this long-distance lifestyle -- songbirds, literally, inhabit entire continents in both Northern and Southern hemispheres as each year progresses -- that the message about what happens far away has finally begun to be acknowledged to have profound relevance locally. The globe, that is, really is one big, interconnected web; however tired the image, its intricate, subtle connections span the entire planet.

For example, when unregulated quantities of pesticides, some of which are now forbidden in the United States, are used heavily and/or incorrectly in Central and South America, not only do birds suffer and die there, but also their failure to return to North America or their difficulties reproducing successfully if they do manage the long journey, signal hazards we may not have noticed yet, but must become aware of and not continue to ignore. Once again, these small birds are our canaries in the mine. That their numbers dwindle year by year, decade by decade, with little or no sustained improvement, signifies a serious, long-term problem.

Stutchbury makes many convincing cases for doing the right thing: buying shade-grown coffee instead of beans from slash-and-burn properties, turning off lights at night during spring and autumn migration times, choosing recycled paper and forest products certified by the Forest Stewardship Council, selecting organic produce both from Latin America and North America, avoiding crops that pose the greatest chemical risks to birds (alfalfa, Brussels sprouts, blueberries, celery, corn, cotton, cranberries, potatoes, wheat), and keeping cats indoors.

Sadly, the writing itself is awkward, disorganized and repetitive, peppered with cliches and grammatical errors, but the book's message is so important, the writer's earnest belief in her thesis and that of a growing number of like-minded scientists so enlightening, that linguistic problems may take a backseat. Here is an essential primer for any person who cares about our planet as a whole, or about our immediate environment. It's an eye-opener, to bird watchers, and an introduction that once again illuminates how nature is subtle beyond our humble efforts to comprehend.

Stutchbury spends part of each year in Ontario and the rest in Pennsylvania. A migrant herself, therefore, she exudes an insightful empathy for her study subjects. Her analogies are apt: A fragmented environment full of visible and invisible threats, with poor resources and high predation, would strain any animal's ability to succeed. The metaphor should be easy to apply: If we can, as individuals, learn to make caring choices about what we buy and how we live, if we can think of others on whom we depend -- perhaps, unknowingly until now -- each contribution, however tiny, will be a step in the right direction.

Irene Wanner is a New Mexico writer.

This article appeared on page M - 1 of the San Francisco Chronicle

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