Friday, 27 July 2012

The eye of the kestrel

The southerly drift of birds at the end of the breeding season is just starting on the island, a sign of the seasons moving on. A young kestrel appeared today and I was lucky enough to find it hunting this afternoon from a perch on the Mainlight. Every so often it would plunge down from its perch to the bank below the Beacon, grab a prey and head back up to its perch again. I was watching it through binoculars and could see that it was catching small objects that may have been beetles and it gave me a clear idea of just how good a kestrel's eyes are. With my x 8 binoculars and standing the same distance of about 30m away I couldn't see  exactly what the bird was picking up but the kestrel could spot them and also identify that they were food. In fact kestrels have a massive density of cone receptors in their eyes  which enable them to spot small things such as bugs from great distance. Another adaption they have is the ability to see ultra violet light. This helps them catch another of their prey, small rodents as mice and voles leave a trail of urine and poo as they move about the vegetation as a trail for others to follow. Kestrels can see the light reflecting on this trail and move in for the kill. It does make you wonder just what the world looks like through a kestrel's eye.

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