Light pollution can be very disorienting for many animals that rely on natural cues to find their way. For sea turtles, artificial light is a major problem. Hatchling sea turtles use the bright reflection of the moon on the ocean horizon to find the water. When bright lights from buildings or roads shine near a beach, the turtles crawl toward the light instead of the sea, which can lead to dehydration or being eaten by predators. Most studies show that short wavelengths, such as blue and white light, are particularly disruptive to their navigation.
Migratory birds face similar issues during their long journeys. Many birds travel at night and use the stars or the moon to guide them. Bright artificial lights from cities can confuse their internal compasses, causing them to fly off course or collide with illuminated buildings. Blue light is highly visible to many species and can interfere with their natural rhythms. To help these animals, experts recommend using warmer colored lights, like amber or red, and shielding outdoor lights so they point downward rather than toward the sky.
