Senses

Central nervous system (CNS) - composed of brain and spinal cord

Peripheral nervous system (PNS) - consists of the nerves found throughout the body (not brain and spinal cord)

Sclerotic plate - has a role in supporting the eye in animals without spherical eyes

Pecten ​- a structure of the choroid whose function is to nourish the retina and controls the pH of the eye

Fovea ​- the area where the cones in the retina are concentrated assissting visual perception

Nictitating membrane - a transparent/translucent eyelid that can be drawn across the eye for protection and to moisten it while maintaining visibility

Primaries - flight feathers on the outer wing that are attached to the manus

Secondaries - flight feathers of the inner wing that are attached to the ulna.

Alula - are not flight feathers, but aid to slow flight during landing increasing lift delaying stalling

Covert feathers - help to smooth airflow over the wings and tail and cover other feathers making the structure more rigid

Preening - feather maintenance behaviour in which a bird tends to its feathers with its bill