www.ukbutterflies.co.uk

As bird beak marks are so common on butterfly wings,I was wondering if there have been any studies done on the subject ?

It's well known that many of the markings on butterfly wings are intended to divert birds' attention (and lizards' attention, too) away from the butterfly's head and towards parts of the wings where damage will not kill the butterfly or affect its mobility too much - butterflies can fly adequately on surprisingly tattered wings. Good examples of these defensive markings are the eye-spots on many browns and blues, and the white lines on hairstreaks diverting attention away from the head of the butterfly. The 'tails' on some hairstreaks and blues serve as false antennae and suggest that the head is at the other end of the butterfly to where it actually is.

Here are Blue-spot Hairstreaks from southern France, which employ most of these measures:
They work, too!
Here is a Pearly(?) Heath that has very conclusively lost an eye-spot but is otherwise none the worse for wear:

Many thanks Matsukaze, Also see this link.

http://www.eastscotland-butterflies.org ... 1926#p1926

An extremely interesting subject indeed !