Second, you may think of a bird like a hawk or owl, and marvel at the ability that these predators have of stalking their prey, using acute hearing and eyesight. Owls can in fact hear mice rustling along the woodland floor, and hawks can see tiny prey on the ground as they circle hundreds of feet high in the air. Both these aspects of the bird nervous system are true, although there are exceptions. If you keep a pet parrot, you may well marvel at the bird's seeming intelligence. Parrots not only learn to mimic human speech and other sounds, but they have an uncanny ability to react in ways that demonstrate intelligence.
Birds also lack several senses altogether.
Birds cannot smell or taste, which explains why even the most 'intelligent' bird will peck at a piece of plastic as readily as a tasty morsel of food.