Meeting Abstract

48.4  Sunday, Jan. 5 10:45  Looking above the prairie: localized and upward acute vision in a native grassland bird TYRRELL, L.P.*; FERNANDEZ-JURICIC, E.; Purdue University; Purdue University ltyrrell@purdue.edu

The visual system of open habitat vertebrates is predicted to have a band of acute vision across the retina (visual streak) and a wide angle of visual coverage to gather information along the horizon. We tested whether the eastern meadowlark (Sturnella magna) had this visual configuration given that it forages and nests in open grasslands. Contrary to our expectations, the meadowlark retina has a localized area of acute vision (fovea). The fovea projects above rather than towards the horizon when the head is at rest, and individuals modify their body posture in tall grass to maintain the same foveal projection. Meadowlarks have relatively large binocular fields and are able to see their bill tips, which may help with their probing foraging technique. Overall, the meadowlark visual system does not fit the profile of vertebrates living in open habitats and may be specialized in detecting and tracking aerial stimuli (predators, conspecifics).