Meeting Abstract

P2.11  Sunday, Jan. 5 15:30  From the Individual’s Visual Perspective: How Foraging Behavior is Related to Chromatic Contrast of Seeds and the Retinal Physiology of Individual House Sparrows TODD, G.J.*; ENSMINGER, A.L.; PEARSON, T.L.; FERNANDEZ-JURICIC, E.; Purdue University, West Lafayette, IN; Purdue University, West Lafayette, IN; Purdue University, West Lafayette, IN; Purdue University, West Lafayette, IN gtodd@purdue.edu

The configuration of the visual system plays an important role in foraging behavior of organisms that rely heavily on vision to locate food. Factors such as the location of the fovea, the width of the binocular field, the density of photoreceptors, and the absorbance properties of photoreceptors combine to determine how easily organisms identify food items against substrates. We hypothesized that these factors can affect head movement rates, head positions, and seed-finding rate. We tested this hypothesis in house sparrows in two treatments: seed against high-contrast and low-contrast backgrounds. We predicted that individuals would have a higher seed-finding rate in the high-contrast background and that there would be a difference in head positions between the two treatments. We will present head movement rates, the proportion of time spent in various head positions, and the seed-finding rates, in relation to chromatic contrast. For these individuals, we also collected data on photoreceptor densities and oil droplet absorbances (components of an individual’s ability to discriminate colors). Having both behavioral and physiological data allowed us to test whether an individual’s behavior is related to its visual physiology. We predicted that individuals with higher photoreceptor densities would have higher seed-finding rates in both treatments, due to having higher visual resolution. We also predicted that the oil droplet absorbances of individuals would affect performance in the two trials, perhaps differently in the two treatments due to the difference in chromatic contrast. This study has implications for understanding the relationship between visual physiology and foraging behavior.