Geography Reference
In-Depth Information
has reserved for nature and clean water, we found a few more species, usually
twenty birds that are typical of northwestern forests such as Townsend's,
Wilson's, and black-throated gray warblers; chestnut-backed chickadees;
Swainson's thrushes; pileated woodpeckers; and Pacii c wrens.
We expected the suburbs between the city center and the forested re-
serves to support an intermediate number of species, but when we listened as
these neighborhoods awoke each morning, we were astonished! We did not
hear the
hoot
of the endangered spotted owl or the
keer
of the rare marbled
murrelet, but the dawn chorus of thrushes, tanagers, wrens, towhees, i nches,
crows, and woodpeckers quickly cleared the stif est cobwebs from our brains.
Here we often tallied thirty or more species in a ten-minute count. We found
those birds from the industrial city mixed with some of those from the pro-
tected forest. And we encountered a whole new set of birds that use more open
country such as violet-green swallows, willow l ycatchers, killdeer, orange-
crowned warblers, American goldi nches, and Bewick's wrens. Ethereal music
typical of open headlands or the tundra serenaded us, courtesy of male white-
crowned sparrows.
Compiling standard bird surveys from more than one hundred locations
in and around Seattle revealed to us a consistent, but unexpected, relationship
between the intensity of development and bird diversity. The greatest diversity
was not in the most forested setting. Instead, bird diversity rose quickly from
the city center to the suburbs and then dropped again in the extensive forest
that eases Seattle into the high Cascades. We had discovered
subirdia.
Now I was really perplexed. Suburbs, you see, are not only rich in birds,
but they are the preferred habitat of my fellow Americans. First designed in the
mid-1800s outside New York City and Chicago, suburbs now house more than
40 percent of all U.S. residents. Our suburban lifestyles were made possible by
advances in transportation and agriculture. Level and cleared farmland around
cities was available for settlement through the 1900s as farmers were able to
increase yields i vefold and ei ciently ship goods from distant farms to urban
