The common names of birds in various parts of the world often use hawk in the second sense. For example, the Osprey or "fish hawk"; or, in North America, the various Buteo species. In February 2005, the Canadian ornithologist Louis Lefebvre announced a method of measuring avian "IQ" in terms of their innovation in feeding habits. Hawks were named among the most intelligent birds based on his scale. Hawks are widely reputed to have visual acuity several times that of a normal human being. This is due to the many photoreceptors in the retina, an exceptional number of nerves connecting these receptors to the brain, and an indented fovea, which magnifies the central portion of the visual field. Enjoy 14 sounds of this great hunter