I was recently on a tiny island in Puerto Rico and noticed they had changed all their streetlights to red. It turns out they were confusing turtle hatchlings. T

I was recently on a tiny island in Puerto Rico and noticed they had changed all their streetlights to red. It turns out they were confusing turtle hatchlings. The hatchlings would normally follow the moonlight out to sea but were being confused by the streetlights and would end up dying after going the wrong direction away from the water. Apparently the red light is not as visible to them so they don't get confused. I don't know if red light would help with light pollution, but I do sometimes wonder if streetlights could be hooked to motion sensors and only turn on when there are people or vehicles approaching. There are so many towns where most of the time the streetlights are completely useless. I have seen this work in offices with motion sensors for each room or zone that turn the lights off automatically when nobody is around. I would think the sensors would pay for themselves in electricity savings over several years.