I wasn't aware that pidgins [sic] were damaging Silbury Hill. Now if we could train thousands of them to fly over the top we could have that hole filled with white stuff in no time.

BTW, the best pigeons for plain roasting are the young ones that haven't yet got their "stripes" (the white flashes each side of the neck), but older birds are delicious pot-roasted. Stuff them with tart grapes, put them in a pot with a little stock and some dry white wine and slow roast for an hour and a half.