If it's not a crime to pick a favourite bird then mine's the Kestrel. With rich chestnuts, downy browns and the male's characteristic slate blue head, the Kestrel's plumage leaves little to be desired. Inks black strips sit below the falcon's eyes, these watercolour like strokes are not simply for display, each minute feature serves a definitive purpose. The markings are known as malar stripes which deflect excess light from raptor's eyes and absorb the light on account of the black pigment. An idea adopted by American footballers.
However of all the Kestrel's adaptations, it's their remarkable ability to hover which fascinates me, an ability shared only by the Barn Owl in Irish bird species. Kestrels achieve this feat of flight by using their supremely adapted wings to not only apply enough thrust to remain air born, but detect and manipulate rising air thermals. The falcon's uses it's broad tail both stabilise and direct itself. All decisions made by the Kestrel while hovering are literally made in milliseconds. The raptor's head remains motionless during the hovering which allows it to use its ultra violet vision to its best advantage.
Raptor's ability to see in ultra violet is a direct function of the structure of their eye. The retina, the photosensitive membrane in the eye, is over 1.5 times thicker than ours in raptors. Raptors also have high cone and rod cell numbers. Cone cells act as photo receptors while rod cells process and filter extreme low light. All contributing to their ability to track mammal blood and urine trails, on account of their ultra violet vision. Considering 75% of a raptor's skull is occupied by their eyes, it is to be expected that exceptional sight be one of their attributes.
The Kestrel is a truly remarkable falcon and a product of several million years of evolution and natural selection at it's best, stealing the top spot as my favourite bird.
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