The other example I remember of the corncrake's limitations was seeing one fly out from the long grass in a field being cut for silage - straight into a stone wall! And that f***er was expecting to be able to fly to south west Africa and back within a few months! ;>)

More seriously, of course, farmers were eventually encouraged to postpone such cutting in sensitive areas - and to cut from the inside outwards when they did, allowing birds to escape through the long grass into neighbouring fields.