Use of cover crop fields by migratory and resident birds

Cover crops, established between the growing seasons of primary crops to improve soil and water quality, have become increasingly popular in the Midwest region of the United States; however, the impact on migratory and resident birds is largely unknown. We conducted avian surveys on four field types in east central Illinois in the spring of 2015 and 2016: maize (Zea mays L.) stubble with cover crop, maize stubble only, soybean [Glycine max (L.) Merr.] stubble with cover crop, and soybean stubble only. For each field type, we calculated relative bird abundance and the Avian Conservation Significance value (ACS). Relative bird abundance was greater in cover crop fields than non-cover crop fields, with the maize fields planted with cover crops providing the greatest value (nearly twice the number of individuals and twice the species compared with non-cover crop soybean fields). The most common species were Red-winged Blackbird (Agelaius phoeniceus), Common Grackle (Quiscalus quiscula), and American Robin (Turdus migratorius). ACS values were most influenced by the Eastern Meadowlark (Sturnella magna), a species of high conservation concern. Many agricultural landscapes lack habitat in the spring and cover crop fields may be important areas to provide shelter and forage for birds. While we documented greater use of these fields more research is needed to understand why birds use these fields; more explicitly are birds finding cover, foraging, or attempting to breed in cover crop fields? As the amount of cover crop area increases, the value of these fields for migratory and resident bird use may increase. While habitat for wildlife is a secondary consideration when planting cover crops, my research suggests the use of cereal rye and later termination of cover crops benefits birds. Cover crops will not replace natural habitats for birds, but the widespread use of cover crops may benefit some bird populations.