Study shows crimson clover increases bird populations

Posted 7:57AM on Sunday 7th July 2002 ( 22 years ago )

TIFTON - Sharad Phatak has been singing the praises of crimson clover for revitalizing lifeless farmland for years. Little did he know that while restoring nutrients and organic material to the soil and attracting multitudes of pest-fighting insects, the red-flowering plant could also help quail and other dwindling bird species. ``I don't even know one songbird,'' said the 70-year-old horticulturist at the University of Georgia's Coastal Plain Experiment Station in Tifton, 200 miles south of Atlanta. ``I'm not a bird man. I have birds in my yard, but I don't know what they are, except ... crows.'' Two wildlife biologists and a graduate student in the university's school of forest resources found that the bird population in cotton fields increased significantly when cotton was planted between strips of crimson clover. Others have examined the mixing of other plants with cotton to save money, control erosion and increase soil fertility. But the Georgia study is the first to look at how they could affect wildlife. The two-year study in Burke, Jefferson, Washington, Jenkins and Johnson counties focused on about 60 types of birds, including several species of concern, such as the blue grosbeak and the dickcissel, which spend their winters in Latin America and fly north to breed. Other neotropical migrants included the grasshopper sparrow, the great-crested flycatcher, the summer tanager and the yellow-breasted chat. John Bianchi, communications director of the National Audubon Society, said 30 percent of American songbirds have been lost since 1970. They're declining at a rate of about 4 percent per year. ``It's a massive amount,'' he said. ``The main reason for this is not agriculture. In fact, agriculture has a relatively small impact. The main problems tend to be habitat destruction and degradation, which impacts fully 90 percent of birds.'' He cited golf courses as an example of degradation ``Developers think they're doing well. They take a chunk of sensitive land and replace it with a lawn,'' Bianchi said. ``Bluebirds and hawks visit the course. But bluebirds and hawks exist in New York City. They should not be your barometer.'' The Georgia biologists studied the feeding, nesting and breeding patterns of birds in three types of cotton fields: cotton growing amid crimson clover, no-till cotton and cotton growing in conventional fields. They noticed the most dramatic differences during the spring breeding and nesting season. ``There were three to four times more birds, which translates to 300 to 400 percent more birds, in clover than in the no-till,'' said biologist Bob Cooper, who helped design the study. ``But there were 10 to 12 times as many birds in the clover than in the conventional tillage.'' Conventional cotton fields are deeply plowed and harrowed until they are free of vegetation. Then the seeds are planted and the plants are nurtured with hefty doses of fertilizers, pesticides and other chemicals. ``Other than the cotton plants, there's really not much else there at all,'' Cooper said. ``Its a biological desert.'' No-till farmers plant the new crop with as little disruption of the soil as possible over the stubble of the previous crop. Very few farmers use the clover method. Those who do, cover the field with clover and then use a herbicide to make narrow strips where they plant cotton seed using the no-till method. Georgia farmers will plant about 1.5 million acres of cotton this year, an area nearly twice the size of Rhode Island. ``It's a huge chunk of land,'' said John Carroll, the other biologist involved in the study. ``If only a portion went into this sort of system, it would have a phenomenal impact on songbirds.'' Sandy Cederbaum, the graduate student who monitored the fields, said conventional fields provided no food and no cover to protect birds from predators in winter. No-till and clover fields both provided significant food and protection. ``During winter, clover and (no-till) fields had similar numbers (of birds), while levels were so low on conventional fields, densities could not be determined,'' she said. The clover fields seem to attract more birds because they have higher bug populations, the researchers said. One of Phatak's experimental plots in Tifton is teeming with ladybugs beneficial insects that help control pests. His studies have shown that crimson clover can make fields more fertile, infuse the soil with moisture-holding organic material and cut production costs by reducing farmers' reliance on pesticides. Phatak began alternative-cropping research 17 years ago to improve the soil, to help family farmers survive by reducing their costs and to provide an alternatives to chemicals. ``The wildlife habitat study opened my eyes as to the other beneficial aspects of the system,'' he said. ``Pesticides have been blamed for the destruction of wildlife, but here we have a system that promotes wildlife.''

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