The Caterwauling Charm is a spell that will create a large screeching noise if someone sets it off within the designated area, which seems to be possible just by moving. It does not pinpoint where the charm was triggered and it is probable that it can be set to only apply out of doors and to not apply to certain people. When the Death Eaters created a curfew in Hogsmeade village in case Harry Potter arrive, he and his friends set off the charm by Apparating into the area. However Aberforth Dumbledore claimed to have been the culprit, saying that he had put out the cat. The Death Eaters believed his story.