In the stationary radar experiment 1A, we did not find effects of the substrate color on any behavioral response, which suggests that the degree of visual conspicuousness of the food items did not influence foraging behaviors. Previous work (e.g., Siddiqi et al., 2004) has set a range (1–4 JNDs) at which items are difficult to discern from the background. In our study, the visual contrast of the seeds was much higher than 4 JNDs. It is possible that we did not find significant effects of substrate color on foraging behavior because the foraging task was not visually challenging enough.