Best bug control?
<p>This Jan. 23, 2005 photo shows an Eastern bluebird photographed near McLeansville, N.C. Eastern bluebirds are voracious insect feeders, especially during nesting and rearing periods. Their primary diet includes flies, katydids, beetles, worms and spiders. They're aerialists, catching insects on the fly or pouncing on them on the ground.</p>
Growers are beginning to understand that common birds can be of uncommon value to fields, lawns and gardens.
Many avian species earn their keep by eating insects and small mammals, and destroying weed seeds.
"Commercial growers are turning to birds as an alternative or supplement to pesticides," said Marion Murray, an Integrated Pest Management project leader with Utah State University Cooperative Extension. "But you have to have the environment or habitat before inviting them in."
That means mimicking nature by providing plenty of food, water and cover. Put up some bluebird boxes or nest boxes for raptors, said Marne Titchenell, a wildlife specialist with Ohio State University Extension.
"Monitor the bluebird boxes so sparrows don't take over," she said. "Brushier habitat provides protection for insect-eating songbirds. Allow the edges of your woodlot to grow up a bit. Berry-producing shrubs are excellent things to have around for all kinds of wildlife."
Birds occupy a unique place in nature, according to the authors of a timeless 1912 study, "Red Bird, Green Bird: How Birds Help Us Grow Healthy Gardens," by Harry A. Gossard and Scott G. Harry (Ohio State University Extension, revised edition 2009). "Each species performs a service which no other can so well accomplish," the authors said.
Raptors such as hawks and owls chase down field mice, moles and grasshoppers. Insectivores like bluebirds, chickadees and woodpeckers stalk beetles, worms and grubs.
Meadowlarks are ground feeders, favoring meadows and farm fields where they gorge on grasshoppers and weevils. Robins focus on lawns and gardens, where they pull up cutworms, wireworms and other larvae injurious to crops.
Chickadees are birds of the forest, eating tent caterpillars, bark beetles and plant lice. Goldfinches prefer open country where they can pursue caterpillars and flies. "No other bird destroys so many thistle seeds," the authors say.
"An individual tree swallow, barn swallow, purple martin or chimney swift can eat up to a thousand flying insects a day," said David Bonter, assistant director of Citizen Science with the Cornell Lab of Ornithology. "They can have a big impact."
While it's great to have these specialized bug hunters around if you're a grain farmer, small commercial farmer or orchard grower, recruiting should be directed toward a variety of species, said Margaret Brittingham, a professor of wildlife resources at Penn State University.
"All insect eaters feed at different heights, on different plants and prefer different insects," she said. "Having some (bird) diversity is important in maintaining insect populations. What we don't want to wind up with is having a monoculture with birds as we frequently do with plants, inviting problems."