Whole Life Times: Destination Unknown

March 2008 | Art & Soul

Destination Unknown

Interview by Jamie Friddle

Animals are the original world travelers. Consider the North American warbler. In Canada and the United States, about 50 species of this songbird cruise a “flyway” — a highway for migratory birds — from Canada, where they breed in summer, to Central and Latin America where they round out their winter months. There and back it’s more than 10,000 miles — with only the stars and earth’s magnetic field guiding them.

It’s called migration, and it’s part of the natural order of things — or at least it was. But a new book by Princeton’s David Wilcove portends that migratory species may be a dying breed. Habitat destruction, human-created obstacles, over-exploitation and climate change threaten the flyways these animals have used for centuries. “Simply stated,” Wilcove, a professor of ecology and evolutionary biology, writes in No Way Home, “the phenomenon of migration is disappearing around the world.”

We caught up with Wilcove for a chat about why we should fight to protect the migratory way of life and what we stand to lose if we fail.

Why did you write No Way Home ?
I’ve been a birdwatcher since I was a little boy, and if you’re a bird watcher there is nothing more exciting than the spring or fall migration. But I was also aware that bird migration in the United States is becoming an increasingly less impressive and exciting event as bird populations decline. At the same time, I was becoming aware of the fact that other migratory species were declining as well. I felt it was important to put that message together in a single book.

Why should we care about preserving
migratory patterns?
First, animal migrations are among the most awe-inspiring spectacles in nature. Second, animal migrations play an important role in maintaining the health and vitality of our world. Migratory songbirds that sweep north in the spring are consuming many times their body weight in insects, targeting insects that feed on the leaves of trees, [which in turn is] helping to maintain the health of our forests. As the number of migratory songbirds decline, there will potentially be more defoliating insects out there to stress the forests. And third, traditional migratory animals have been an important resource for people, whether it’s salmon, or waterfowl or migratory fish that we consume.

One of the things I learned in researching the book is the important ecological role that migratory species play in their full abundance. A classic example would be salmon in the Northwest. The salmon [serve as] a method for taking nutrients from the rich ocean environment and bringing them back to the rivers. When the salmon decay, they release important nutrients such as nitrogen that they have gathered in the ocean to the stream system. The nutrients are [also] transported onto the land by the predators that eat them. So if you look to the wine-country, California, a significant fraction of nitrogen growing in the leaves of the grape plants is derived from salmon. So many of our western rivers are now suffering a deficit of nutrients because they no longer have these large populations of salmon.

The geopolitics of conservation seem daunting. What first step can nations take to collaborate on conservation of migratory species?
These migratory animals cross all sorts of administrative and political boundaries, boundaries that are absolutely meaningless to them but terribly meaningful to us. So it’s clearly going to require a level of cooperation that we haven’t seen before, both at the national level and at the international level. I would argue one of the most important steps will be the prosaic step of electing political leaders who recognize that not just migratory species but a whole range of environmental problems [can only be addressed by] a cooperative international dialogue. It’s an issue for every nation, because you can’t find a country that does not have animals migrating across its borders.

What is the greatest threat to animal migrations right now?
Habitat destruction remains the most widespread and the one that is here and now destroying migratory routes for a wide range of species.

Looking ahead, I think climate change will disrupt a significant number of animal migrations. Certainly rising sea levels will in all likelihood destroy many of the nesting beaches for sea turtles. Or rising temperatures will disrupt the important patterns of bird migration where songbirds try to time their migrations when insects — caterpillars in particular — are most abundant in the forests. These sorts of relationships between predators and prey, between migratory animal and habitat, are likely to be disrupted.

What is the most haunting situation you encountered in your research?
I think driving through the countryside in South Africa and seeing the degree to which what had once been an open country inhabited by all those great mammals is now converted to agricultural lands where there simply are no large mammals. There’s no longer room for wildebeest, for zebra, for elephants, to migrate as they have for so many thousands of years.

What is the most interesting migration you’ve seen and why?
The two that really took my breath away were the migration of wildebeests in the Serengeti, and an autumn day, about three years ago, in Cape May, New Jersey, where trees and bushes were just covered in songbirds.

Jamie Friddle lives and writes in Seattle. He and his girlfriend love to feed hummingbirds.

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