baltimoresun.com
What's killing America's songbirds? Pesticides, roads, cats, even coffee
By Tom Pelton

Sun Reporter

July 29, 2007





ReviewEnvironment
>>>Silence of the Songbirds
By Bridget Stutchbury
Walker & Company / 255 pages/ $24.95 



In the steam swirling from your morning cup of java could be the ghosts of Baltimore orioles and other songbirds snuffed by the coffee industry. 

This haunting image is conjured by biologist Bridget Stutchbury in her new book, Silence of the Songbirds. And implicit in her picture is a message that people can take steps to stop worldwide declines in songbird populations. For example, you can get your caffeine from a beverage that doesn't require the clearing of tropical forests. 

Consumer action is necessary, Stutchbury argues, because half of the songbirds in the Americas have disappeared since the 1960s. Not only are Baltimore's signature songbirds vanishing, but so are eastern kingbirds, Kentucky warblers and dozens of other species that make annual migrations to the tropics. 

Stutchbury's book is an encyclopedia of the threats faced by songbirds, from deforestation to development, light pollution, pesticides and parasites. Her style is lucid and precise and as easy on the ear as a wood thrush's song. But it occasionally wings into academic thickets, getting tangled in yawn-inducing paragraphs in which Stutchbury, a Yale-educated professor at York University in Toronto, tediously enumerates dozens of studies performed by her fellow bird researchers. 

But for people with a passion for birds, it's readable - and powerful. In its warnings about the future, Stutchbury parallels Charles Clover's The End of the Line (which describes the depletion of fish populations worldwide) and Barbara Brennessel's Diamonds in the Marsh (about threats to the diamondback terrapin). 

The title of Silence of the Songbirds echoes Rachel Carson's Silent Spring, which warned in 1962 that that DDT and other pesticides were decimating bird populations. DDT was banned by the United States by 1972, and while some species recovered - notably bald eagles and other raptors - songbird populations continued to plummet for the next three decades. 

The decline kept going for migrating birds because the problem was much broader and more complex than just pesticides, Stutchbury points out. The proliferation of brightly lit smokestacks and cell-phone towers led to countless fatal collisions with birds, which get confused when artificial lights replace the stars they rely on to guide their nocturnal migrations. 

Highways have knifed through their forests, fragmenting their breeding grounds. And the expansion of suburbia has unleashed an invasion of house cats - 75 million prowlers in the United States and growing. These pets are often allowed to roam free, and they kill hundreds of millions of birds a year, Stutchbury estimates. 

Worse, the ban on DDT didn't end the threat from pesticides. The ban just convinced farmers to switch to other brands of bug-killers that don't linger as long, but which, in exchange for their more rapid decay, are 100 to 1,000 times deadlier. That means that millions of birds continue to be killed by pesticides today, but it's harder to track, because the new generation of poisons disappears from the corpses before investigators can find the evidence, Stutchbury writes. 

And then there's your coffee to worry about. Many songbirds migrate during the winter from Canada and North America to coffee-growing regions of Central and South America, where they depend on tropical forests as habitat. The expansion of coffee plantations into areas of tropical forest was not a threat for much of the 19th and 20th centuries, because farmers typically planted arabica coffee beans, which grew best in shady places, sheltered by trees. 

But then in the 1980s and 1990s, the U.S. Agency for International Development pushed farmers to cut down all these trees and switch to a different variety of coffee, robusta, which grows better in the sun, according to the book. The deforestation was inspired by a fear of a fungus, called coffee leaf rust, which thrives in shady, moist environments. This spurred a widespread change from "shade" coffee (grown with arabica beans) to "sun" coffee (grown with more bitter robusta beans). 

"The population declines of Baltimore orioles and Tennessee warblers on their breeding grounds coincide with the dramatic conversion of shade to sun coffee," Stutchbury writes. "We cannot give up our coffee but we can insist it to be grown under trees." 

To market themselves as more environmentally responsible, some coffee companies are now identifying their beans as "shade grown" or "sustainable." Stutchbury urges her readers to spend a little more choosing these brands. She also argues that people should keep their cats inside, buy organic produce and insist on recycled paper (to minimize the cutting down of Canadian forests). 

Stutchbury argues that we should care because if the songbirds stop singing, the silence will signal a warning about the health of our environment like the death of canaries in a coal mine. "There is good reason to believe that the angels are slowly falling from the sky, dwindling in numbers year after year," she writes of the decline in songbirds. "We have learned the hard way that when birds begin disappearing, we may be next." 



Tom Pelton covers environmental issues for The Sun.