Owl Physiology Owls have certain physiological advantages that give them an advantage when hunting prey. Owls have the best night vision of all birds of prey. In addition to having excellent vision, their hearing aids allow them to hunt at night. Their wings have also evolved to produce almost silent flight, allowing them to sneak up on prey. Owl Vision Being nocturnal, owls need the ability to see in the dark. They have developed excellent vision that adapts to the amount of light they are in. This means they have exceptional vision day and night. The basic structure of an owl's eye is similar to that of a human's. It is made up of a cornea, a pupil, an iris, a lens and a retina. The major difference that gives an owl night vision is the concentration of light-sensitive rods in the retina. The retina is made up of rods and cones, each performing a different function. Rods are designed for low light environments and cones are better suited to high light environments (Scholz, 2001, p. 3). The iris can expand or contract, depending on the amount of light, giving owls the ability to see in any amount. of light. During the day, the iris contracts, causing the pupil to narrow. Less light passes through the lens and reaches the retina. At night, the iris enlarges, making the pupil larger, which allows more light to pass through the lens. Once through the lens, light enters the retina. An owl has many more rods than cones, giving it the ability to convert small amounts of light into an image. This gives them an advantage when hunting at night. Owls also have a more tubular shaped eye, as shown in Figure 1, compared to a human's eye. This gives the cornea a larger size in proportion to the overall size of the eye, allowing...... middle of paper ......ability-to-fly-in-acoustic-stealth-provides- -clues-for- Mitigating-Conventional-Air.pdf Dobkin, DS, Ehrlich, PR, and Wheye, D. (1988). From How Owls Hunt in the Dark: https://www.stanford.edu/group/stanfordbirds/text/essays/How_Owls_Hunt.htmlLewis, D. (nd). Tawny owl skeleton [Online image]. Retrieved from http://www.owlpages.com/image.php?image=articles-Owl+Physiology-Skeleton-01Scholz, F. (2001). Owls. Mechanicsburg, PA: Stackpole Book. Sieradzki, A. (n.d.). Diagram of the owl's digestive system. [Online image]. Retrieved from http://www.owlpages.com/image.php?image=articles-Owl+Physiology-Digestion-1.5Winkler, S. (2008, July 14). How can owls fly silently. Retrieved from How Stuff Works: http://science.howstuffworks.com/zoology/owl-fly-silently1.htmWorld Owl Trust. (2012). View. Retrieved from World Owl Trust: http://www.owls.org/Information/eyesight.htm