In addition to eagles, birds such as hawks, falcons, and robins have extraordinary vision which enable them to gather their prey easily. Their eyes are stated to be larger in size than their brain, by weight.[2] Colour vision with resolution and clarity are the most prominent features of eagles' eyes, hence sharp-sighted people are sometimes referred to as "eagle-eyed". Eagles can identify five distinctly-coloured squirrels and locate their prey even if hidden.[3]