A canary in a coal mine
In “Silence of the Songbirds: How We Are Losing the World’s Songbirds and What We Can Do to Save Them,’’ Bridget Stutchbury alerted the world to an alarming decline in songbird population resulting mainly from habitat destruction, environmental pollution, and climate change. Stutchbury’s latest book, “The Private Lives of Birds: A Scientist Reveals the Intricacies of Avian Social Life,’’ analyzes the social lives of birds along with the evolutionary and environmental explanations for their behavior. Whether she is describing a Pennsylvania forest or a Panamanian jungle, Stutchbury is as entertainingly informative about our species as she is about the avian world. She lives in Ontario and Pennsylvania and spoke from York University, Toronto, where she is a professor of biology.
Q. What are your thoughts on the oil disaster in the Gulf of Mexico?
A. A theme of this book is the omnipresence of people in birds’ lives. Even birds on remote islands in the Southern Hemisphere cannot escape the impact of humans because there are just so many of us, and we do so many crazy things when it comes to the environment. What strikes me with this disaster is that the potential scale of bird deaths should make us realize that our everyday pollution also affects birds in more subtle ways and that all birds are affected.
Q. Can birds adapt to altered environments?
A. There are two ways in which an individual, a population, or a species adapts. One is behaviorally. The American robin, for example, is not that picky about where it nests. That’s an adaptation that can happen quickly because it’s not an evolutionary process. When people assume that birds adapt quickly to new situations they’re probably referring to this behavioral flexibility. Birds that are specialists — in which behavior, habitat choice, mating habits are hard-wired and narrow — can’t readily adapt because this takes many generations. And people often don’t see the birds that are dwindling, only the ones that are moving into their backyards.
Q. Are we still losing songbirds?
A. Yes. Some species are declining by 2 percent per year. Yet because these songbirds were once so abundant, even after decades of oil spills and habitat damage, many of them are still common. There are still wood thrush left, even though we may have lost half of them. But where will we be in another 40 years? Will we have lost half as many again? Environmental policies are not changing as fast as I would like them to, but I am hopeful that it’s not too late to turn things around.
Q. Is it true that the bird song we hear is not the bird song they hear?
A. We hear the same range of frequencies, but birds can discriminate between two sounds that are very close together. What they hear as “dit dit’’ sounds to us like “dit.’’ One way to appreciate what songs sound like to a bird is to slow it down so that our ears can catch up. A robin’s song, for example, sounds more like a whale song with all these weird, drawn-out sounds and changes in frequency. That’s what those birds sound like to each other. There’s all this detail because female birds are listening for how much a male can sing, gauging his stamina, and for how well he sings difficult pieces. There are physical limitations on male performance: how quickly his muscles can fire, how quickly he can open and shut his beak, can breathe. Females listen for rapid sounds close together, for example, and a wide frequency range because technically it’s difficult for a male to go from high to low so fast. What the female hears informs her about the potential father of her precious eggs.
Q. And we don’t see what birds see?
A. Birds see four different color types while we see only three. Because they can see in the ultraviolet the world looks completely different to them; they see more. A color pattern that to us looks boring — say a white stripe on a sparrow’s head — to another bird reflects ultraviolet light and is as stunning as an indigo bunting’s plumage. Bright blue! A beautiful bird! A sparrow!
Q. Do you aim to demystify bird life?
A. Well, it’s ironic to me that we view birds as similar to us when it comes to monogamy, beauty, parental care. We don’t look at our little songbirds with other human traits in mind, like sex and violence, although these are just as prevalent. Of course, it makes evolutionary sense for individuals to be selfish and for females to choose the best mate. When it comes to sex and violence, however, we want to ignore it in our beautiful birds. Yet I think it makes backyard bird-watching and nature walks even more fascinating. These creatures are so incredibly complex. After doing this work for many years I am still awestruck that a little thing with a brain smaller than my fingernail, while it cannot think or strategize, carries so much information in its head, all of it programmed through generations of trial and error.
Anna Mundow, a freelance journalist living in Central Massachusetts, is a contributor to the Irish Times. She can be reached by e-mail at firstname.lastname@example.org.