The US Fish and Wildlife Service is a group of people who work to take care of all the animals and plants that live in the United States. Think of it like taking care of your backyard or your house, but instead of just taking care of your things, they take care of things in all the different states in America!
They help to make sure that there are lots of different animals and plants living and growing in the United States. They also make sure that people don't hurt or harm the animals and plants on purpose.
Sometimes, they even help animals that are hurt or sick by giving them medicine or a safe place to rest until they can go back to the wild.
So, the US Fish and Wildlife Service is a really important group of people who work to keep nature healthy and safe in America.