The loud bang certainly works for scaring the hawks and falcons but for flaging pigeons????? Could it be that when under stress the heart pumps harder, obviously, hence heating the poor wee buggers heat up until gaping? simple explaination? How do you mean it never occurred to you that the birds wer being attacked? surely you would have seen a sparr attack? Peter your ideas and experiences are very different reading from the norm, well done on yer alternative thinking.