The city of Henderson recently declared pigeons a public nuisance. The practical aspect of the law means residents who "encourage the roosting or lingering" of the birds by feeding them will be cited. Why such a fuss? Henderson, Nevada air conditioning contactors say the pigeons are one of the main reasons they are called, explaining that the birds nest on or near the units, and their droppings can corrode the metal and their feathers can flood fans. In addition, the birds carry diseases and can cause damage to roofs. Henderson A/C and heating contractors say the best way to protect your home is to place sturdy steel screens around vulnerable areas.