As grassland has morphed into farmland across the American Midwest, wildlife diversity and abundance have declined. But for some birds things might not be so grim. Some grassland species appear to have adapted particularly well to no-till soybean fields, according to research published in March in the journal Agriculture, Ecosystems, and Environment.
Tilling is a process in which farmers remove weeds and loosen soil before seeding the ground, but no-till farming eschews that practice. Detritus from the previous season's harvest is left covering the ground, where it provides a nice foundation for nesting birds.
That birds were more likely to nest in no-till fields than in tilled ones was not terribly surprising. Rather it was “the extent that birds used no-till [fields], the species of birds we found nesting, and their nest success relative to what we consider quality habitat,” says Kelly R. VanBeek, who conducted the study for a master's thesis at the University of Illinois at Urbana-Champaign.
James Herkert, director of the Office of Resource Conservation at the Illinois Department of Natural Resources, was also surprised by the species diversity in no-till fields, including several “that are of conservation interest such as eastern meadowlark, dickcissel [and] upland sandpiper.” American robin nests were the most common found in both field types, which was also unexpected because robins tend to prefer nesting in trees and shrubs. It “shows just how adaptable they are,” he says.
Nest loss was high in both types of fields, though. The birds whose nests were destroyed by machinery would have been spared if planting were delayed until June 1. But in the past 10 years farmers have planted, on average, 66 percent of soybeans by May 30, in part because soybeans have better yields if planted earlier.
The conflicting needs of farmers and wildlife “make finding win-win solutions challenging,” Herkert says. Still, the researchers suggest that rather than buying small tracts of land to set aside as wildlife reserves, conservationists should work with farmers to implement more ecologically sustainable strategies, such as no-till farming.