Ostrich’s eyes are bigger than its brain
Ostrich eyes are indeed large (it is the biggest bird eye and even larger than that of many large mammals), and bigger than their brains but this does not make them stupid, however. it is not a case of an undersized brain but rather of oversized eyes. Bird brains are generally smaller than in mammals of the same body mass but this reflects the different emphases on sensory perception (such as vision) and the need to process this information.
How big is an ostrich brain?
Ostrich brains may be small compared to the bird but they are more than adequate to allow the bird to sense and respond to the environment in a variety of sophisticated behaviors. Their eyes are, by contrast, very large and provide fantastic eyesight that allows ostriches to see threats and food from a great distance. An ostrich’s eyes are a real asset and, far from hindering the bird’s behavior, they actually help it in its everyday life.