 
 <prompt> Wetin be kestrel? Based on di question wey dey before, write small tori wey get di answer. E fit be 1 - 20 sentences. Context: <response>: Many birds dey show plumage patterns for ultraviolet wey human eye no fit see; some birds wey sexes dey look alike to naked eye dey different by the presence of ultraviolet reflective patches for their feathers. Male blue tits get ultraviolet reflective crown patch wey dem dey display during courtship by posturing and raising of their nape feathers. Ultraviolet light dey also used for foraging—kestrels don show say dem dey search for prey by detecting the UV reflective urine trail marks wey rodents leave for ground. The eyelids of a bird no dey used for blinking. Instead the eye dey lubricated by the nictitating membrane, a third eyelid wey dey move horizontally. The nictitating membrane also dey cover the eye and dey act as contact lens for many aquatic birds. The bird retina get fan shaped blood supply system wey dem dey call pecten. Most birds no fit move their eyes, although there dey exceptions, like the great cormorant. Birds wey get eyes for the sides of their heads get wide visual field, while birds wey get eyes for the front of their heads, like owls, get binocular vision and fit estimate the depth of field. The avian ear no get external pinnae but e dey covered by feathers, although for some birds, like the Asio, Bubo and Otus owls, these feathers dey form tufts wey resemble ears. The inner ear get cochlea, but e no dey spiral like for mammals. 