But now the date is known, public opinion will not tolerate ramping troop numbers back up, the hawk concedes.

ECONOMIST: Lexington

The specialist platform - 75m (246ft) above ground - for the peregrine adults was set up by the Hawk and Owl Trust on the cathedral's spire.

BBC: Norwich Cathedral peregrine falcon lays fourth egg

The Global Hawk can fly missions for up to 36 hours, three times the flying time of a U-2, due to the lifting of pilot restrictions.

CENTERFORSECURITYPOLICY: The Future of Unmanned Flight