For the stationary radar experiments, we captured 91 brown-headed cowbirds for experiment 1A (72 males and 19 females), and 41 for experiment 1B (all males) using six decoy traps located at the National Aeronautic and Space Administration's (NASA) Plum Brook Station, Erie County, Ohio, U.S.A. (41°22′N, 82°41′W). We were unable to capture an even number of males and females for experiment 1A, and we were unable to capture females for experiment 1B. Birds were then transported to and housed in outdoor aviaries (width 2 × length 2 × height 3 m) at Purdue University Ross Reserve, West Lafayette, Indiana, USA (40°24′35″N, 87°4′2″W), where the experiments were conducted. Birds were housed for 1.5 to 3 months before being used in experiments. The enclosures provided areas with shade and wind protection, and contained perches. Animals were housed in groups of 10 to 20 individuals, and were given equal parts of white millet, game bird chow, and sunflower seeds, and water ad libitum. Food was provided in at least 5 small dishes per enclosure, and water was provided in at least 2 large dishes which were heated to prevent freezing in the winter. Food and water were checked or changed every day, and enclosures were cleaned daily.