In the Garden
To Feed
the Birds, First Feed the Bugs
INSECT
BITES Doug Tallamy’s
book “Bringing Nature Home” stresses the importance of nurturing native plants
like goldenrod.
By ANNE RAVER
Published: March
6, 2008/New York Times
Milkweed
Dogwood
DOUG TALLAMY and his wife, Cindy, built their house
seven years ago in the middle of 10 acres of former hayfields.
But they don’t
sit inside much. Most of their spare time is spent cutting Oriental bittersweet
and Japanese honeysuckle out of cherry and oak trees. They saw down thickets of
autumn olive and multiflora rose and paint the cut
stems with an herbicide that goes down into the roots and kills them.
The land was so
thick with multiflora rose that they couldn’t walk,
so Mr. Tallamy cut paths with hand loppers. They work
with handsaws, not a chain saw. And they paint on the herbicide, rather than
spraying it, because they don’t want to damage the treasures below: under those
thorny rose bushes might be seedlings of black oak,
A meadow
cleared of autumn olive can resprout with goldenrod, joe-pye weed, milkweed, black-eyed Susans
and many other natives crucial to wildlife.
It’s hard work,
but the Tallamys love being outside. And they share a
vision, an imperative, really, that Mr. Tallamy lays
out in a book, “Bringing Nature Home” (Timber Press, $27.95), published in
November.
They are
struggling to plant the native species that are needed for insects and animals
to flourish. As exotic ornamentals leap the garden fence and out-compete the
native plants, many creatures are starving to death because they did not evolve
with the exotics and simply can’t eat them.
“I’m not trying
to recreate the ancient ecosystem,” said Mr. Tallamy,
who is chairman of the department of entomology and wildlife ecology at the University of Delaware,
in
He pointed to a
row of white pines he and his wife planted five years ago to screen out a
half-mile racetrack and a 120-stall horse barn as big as a box store. “You
wouldn’t have found white pines here back in the old days,” he said of the
tree. “But a lot of things eat white pine, like sawflies.”
The white pine
is an Appalachian native, and its natural range stops about 30 miles west of
here, he said. But its wide use since Colonial times gradually expanded its
range, allowing its associated insects to hitch a ride.
Last spring was
too cold and wet for moth and butterfly larvae, he said, but the bluebirds
nesting in a box in the meadow were desperate to feed their young. “They found
the sawflies in those pines and raised the entire brood on them, flying back
and forth, back and forth,” Mr. Tallamy said.
Many natives
provide food for insects and birds, and so when young trees sprout in an
inconvenient place — too close to the back door, or in front of a window — Mr. Tallamy delays pulling them out.
“I went to take
this black cherry out and there were 13 tiger swallowtail larvae on it,” he
said, standing by a sapling by the back steps.
He bent over
yet another, even smaller black cherry that had sprouted between the stones of
the front walkway. “Anybody else would pull this out, but see this?” he asked,
pointing to a drab little remnant of a leaf that some young larva had fashioned
into a winter home. “That’s a little hybernaculum for
the red-spotted purple, which is a butterfly that people want in their
gardens.”
Although
gardeners might believe that when they plant a butterfly bush, native to
Even a lowly
fly maggot, which lives inside the hard round galls often seen on the stems of
goldenrod, has an important place in the ecosystem. “Fly maggots are really
high in proteins and fats, and chickadees love them,” Mr. Tallamy
said. “We give chickadees seeds, but when they get one of those maggots, they
can really make it through the cold winter night.”
So if you cut
down the goldenrod, the wild black cherry, the milkweed and other natives, you
eliminate the larvae, and starve the birds. This simple revelation about the
food web — and it is an intricate web, not a chain — is the driving force in
“Bringing Nature Home.”
The book
evolved out of a set of principles that Mr. Tallamy
jotted down at the request of students at the
They all wanted
lists of plants: what attracted what, which was then eaten by what, and so on.
So he began to map a food web for the suburban or urban backyard.
The typical
garden might hold weeping cherries and rhododendrons, lilacs and crape myrtles.
That is beautiful, perhaps, but it’s a barren wasteland to native insects and
thus birds.
Almost all
North American birds other than seabirds — 96 percent — feed their young with
insects, which contain more protein than beef, he writes.
He cites the
work of Michael Rosenzweig, an evolutionary biologist
based at the University of Arizona, who has analyzed data from all over the
world and found a one-to-one correspondence between habitat destruction and
species loss. In
So the message
is loud and clear: gardeners could slow the rate of extinction by planting
natives in their yards. In the northeast, a patch of violets will feed
fritillary caterpillars. A patch of phlox could support eight species of
butterflies. The buttonbush shrub, which has little white flowers, feeds 18
species of butterflies and moths; and blueberry bushes, which support 288
species of moths and butterflies, thrive in big pots on a terrace. (Appropriate
species for other regions are listed by local native plant societies.)
You don’t have
to cut down the lilacs, but they are doing nothing for the insects and birds.
“It’s as if they were plastic,” Mr. Tallamy said.
“They’re not hurting anything, except that they’re taking space away from
something that could be productive.”