When you look up at the night sky, can you see stars? In many cities, it is hard to see stars. Cities have a lot of lights on even at night. Cities have street lights, car lights, and building lights. These lights make it hard to see stars in the night sky.
These lights can cause problems for animals. Some animals get confused by city lights. Some birds need to travel to go to warmer or colder places at different times of the year. They travel at night. Birds are not used to city lights. They get confused about where to go. A few birds even get lost.
Always try to turn off the lights when you are not using them. It helps the planet!