Birds are found in some form on all seven continents - many are very pretty to look at; however they can be come a nuisance and a pest very quickly. Pigeons for example, plague many cities and often leave unsightly droppings as well as tearing open rubbish bags in search of food. Eating seeds at an incredible rate; they can disturb farmers as they plant their crops. Both high and low-tech solutions are deployed - ranging from scarecrows to electronic bird repellers.