Attract birds - not mosquitoes! Because birds love moving water, Water Wiggler works great to attract birds! And it helps prevent the spreading of West Nile virus by eliminating stagnant water in bird baths. Water Wiggler"s unique agitator action creates continuous ripples in water, which prevent mosquitoes from laying eggs in bird baths. Easy to install! Just place the small dome in bird bath and go! No wiring and no plumbing. Operates silently on two D-cell batteries for up to two months of continuous use. May also be used with heated bird bath in winter.