Red Admiral (2)

The same butterfly species I photographed on the 13th of this month but this is the underside instead of the upperside. One of my favourite butterflies just for the sheer size of it (it is one of the largest in the British Isles) and for the amazing journey it partakes in every year from the Mediterranean. The following passage is taken from the magnificent book 'THE BUTTERFLIES OF BRITAIN & IRELAND' by Jeremy Thomas and illustrated by Richard Lewington.

"As befits one of the true European migrants, this butterfly is a supreme flying machine. Its aerodynamics were neatly studied by Adrian Thomas and R B Srygley, who trained adults to fly to and from artificial flowers in a wind tunnel, and took high-speed photos of the trails of smoke disturbed by different wingbeats. They were unable to explain how such a heavy insect could fly so fast and with such manoeuvrability, so using conventional steady-state aerodynamics, they found that the Red Admiral employs an array of unconventional aerodynamic mechanisms that enable it to take off, generate uplift and propulsion, and manoeuvre and land. These include two kinds of leading-edge vortex that create turbulent flows of spinning air over each wing, active and passive upstrokes, an ability to rotate the wings during wing beats, wake capture (whereby the butterfly dips its wings into the swirling air generated by the previous wing beat to recapture some of its energy) and the fondly named 'Weis-Fogh clap-and-fling'. The last mechanism involves clapping the wings together above the butterfly's body and then flinging them apart. As they open, air is sucked in and creates a vortex above each wing, but during the clap the vortex is created on the other side, resulting in a rapid circulation of air that is capable of lifting much heavier bodies than is achievable from conventional leading-edge vortex effects."

I have actually seen my Red Admirals do the 'Weis-Fogh clap-and-fling' when they've been disturbed from the buddleia. They rise up and the noise from the wings is very loud! If you lose sight of it for a few seconds you can actually hear the noise of the clap and the air through the wings so you can relocate the butterfly fairly quickly. Amazing insects they are!

I also managed to get a very bad photo of our resident female Sparrowhawk who sent all the birds into a panic!

Thanks for the comments on my backblips everyone :)