A plan has been announced to turn off the lights on some big buildings in New York City this spring and autumn because of worries about the effect they're having on birds.
As the seasons change lots of birds fly from one part of America to another.
But their journey through New York isn't always so smooth, particularly at night.
That's because birds use the stars in the sky to help them figure out where they're going in the dark.
But with so many bright lights in the city, they get confused and don't end up in the right place.
So the mayor has decided to turn off outdoor lights on public buildings which aren't needed.
From 11pm in the evening, it'll be a whole lot darker for New Yorkers... but hopefully a lot easier for their feathery friends.