Take a walk with any naturalist and prepare to be amazed by their powers of perception.
A faint croak in the distance is an edible frog calling for a mate, that blur overhead is a sparrow hawk swooping for its prey, a small puddle in the mud was made by a badger doing its rounds last night.
It may seem impressive to us mere mortals but do naturalists really have superhuman senses or is it all a trick of perception? Brett Westwood, master of this dark art is decoded by perception guru, Richard Gregory, and is given some tests to do.
Could we all learn to find a beetle in the haystack?