cleggy2: This is how street lights work

The first electric street lighting in one Nelson suburb was powered by a small hydroelectric generator in the hills above the city. To switch the lights on and off, a chicken run was added to the power plant. At dusk every night the hens would go inside their coop and roost on a special hinged perch. This sank under their weight and connected a switch which turned on the street lights. At first light the hens would leave the coop, the spring-loaded perch swung back and the lights went out again.