Pause-Travel Tactics of Foraging Juncos (Junco hyemalis)
Our goal was to develop a greater understanding between relationships of seed density, pause duration, and travel length in feeding behavior of seed-eating Juncos (Junco hyernaIis). How does seed density affect pause duration and travel length? What differences can be observed when the seeds are cryptic? What differences can be observed between detected and undetected seeds? Experiments were designed in order to observe foraging behavior of sparrows in an indoor aviary. Seed densities were set at 16, 32, and 64 seeds/m2. Seed crypticity was also controlled by placing seeds above or below the foraging surface, thus making the seeds flush with the foraging substrate. Generally, pause duration was longer for seeds located in the holes. Pause duration was also longer for undetected seeds versus detected seeds for both cryptic and surface seeds. Travel length for cryptic seeds was longer for undetected seeds. Travel length for detected surface seeds was longer at 16 seeds/m2, but travel length for undetected surface seeds at 32 and 64 seeds / m2 were greater. From the results, we are able to concur with previous research that more conspicuous prey take less time to detect (Dawkins, 1971; Guilford & Dawkins, 1987). As seed density increases, pause duration and travel length should decrease, due to more abundant prey and quicker encounters.