The Natural Resources Conservation Service recently released research conducted by the Conservation Effects Assessment Program (CEAP) evaluating the use of cover crops by grassland nesting birds. The research, conducted in partnership with Iowa State University and South Dakota State University, assessed grassland-breeding bird responses to the integration of cover crops in a corn-soybean cropping system in Iowa.

According to the research, “As currently implemented in a corn-soybean rotation, small grain cover crops are likely not effective for increasing nesting grassland birds in midwestern cropping systems. This conclusion is especially apparent in comparison with perennial conservation cover, like CRP, that showed greater bird use in this and many other studies. Therefore, the positive environmental and agronomic benefits of cover crops appear to have minimal impact on avian breeding habitat use but may have other positive impacts on birds by improving surface water quality and increasing small grain production in the Midwest (e.g., by supplying a market for small grain seed for cover crop plantings). Integrating diverse native perennial vegetation into working landscapes with practices such as field borders, riparian buffers, wetland restoration, or conversion to grass-based agriculture could have positive effects on migrating and nesting bird populations.”

Key Takeaways from the research include:

• Pheasants and other grassland-breeding birds were largely unimpacted by the availability of cereal grain cover crops between corn and soybean rotations.
• Pheasant nest densities were over 20 times greater in native warm season grasses than in cover crop fields.
• Pheasants selected nest sites with greater litter depths and high vegetation densities, which were achieved in cover crop fields only where the previous crop was no-till corn and cover crop growth was exceptional.
• Grassland bird abundance and richness were greatest in perennial grass cover, followed by cover crops, then row crops.
• The grassland bird community found in cover crop fields included all species found in row crops as well as other species, including some found in perennial cover. Perennial cover supported some species not found in either cover crops or row crops.