I sometimes wonder at the sense of those involved though. They almost seem to be asking for trouble.
Its not unusual to see Wokkas at lowish level over the east edge of Morecambe Bay - sometimes overflying the wildlife reserves (e.g. Leighton Moss) and they have a heck of an effect on the birds there. Its only a matter of time before someone gets a pinkfoot goose or other large bird through the cockpit
Its only the helicopters that cause the problem though - not even the Lancaster + two Spits in formation raise a scream from the birdlife.