Among the backroom teams at the Wimbledon tennis championship, perhaps the most unusual is the operation using birds of prey to keep pigeons and other vermin away from the courts and from disturbing the players.Northamptonshire-based firm Avian Control Systems (ACS) fly a Harris Hawk around the courts three times a week.The presence of the bird, named Rufus, is enough to frighten away any pests attracted by discarded food or other scraps."It is a deterrent, and an environmentally friendly and unobtrusive way to keep the courts clear," says ACS boss Wayne Davis.Simon Jack reports