This is a trick question. Where would you expect to find the greatest variety of birds?
Downtown, in a city?
Or far, far from downtown — in the fields, forests, mountains, where people are scarce?
Or in the suburbs? In backyards, lawns, parking lots and playing fields?
Not the city, right?
"Everything I have learned as a conservation biologist tells me cities are bad for biodiversity," writes John Marzluff, of the University of Washington.
We all know this. Anyone who goes to downtown Chicago, Toronto, Seattle, L.A., Boston or New York will see the same five birds over and over: sparrows, starlings, mallards (ducks), geese, and, of course, street pigeons. Same goes for downtowns in Europe, Asia and South America. These five bird types are always there, always the same, never surprising. Rather than yawn, scientists have a category for this: "biotically homogenous." We've made cities. They've moved in.
A Seattle Experiment
But now comes a surprise. Actually, several surprises. When John Marzluff and his students went to downtown Seattle to count bird species, within the first 10 to 15 minutes they spotted pigeons, finches, sparrows, crows and an occasional hummingbird. Their count was 10 to 15 different kinds of birds — not many, but they expected that.
When they went the other way (to the far edge of the metropolitan area near the Cascade Mountains, where there is mostly forest, protected parks, reservoirs, and humans are sparse), in the first 10 to 15 minutes, they found a very different set of birds (woodpeckers, wrens, warblers, chickadees ...). In all, 20 different species — more, but not many more than downtown.
Then they went to the in-between zone, the Seattle suburbs, where they expected an in-between count, something like 12 different kinds of birds. But that's not what happened.