Many birds of Theodore Roosevelt National Park are here only certain times of the year. That is because birds migrate. This is the movement from one place to another. Birds migrate to find the best habitat for the right time of year. Birds migrate mainly to find more food. Many birds lay eggs in the spring or summer because that is when they find the most food. Birds can be herbivores, omnivores, insectivores, or carnivores! Depending on the bird, they will eat seeds, berries, bugs, reptiles, small mammals, and even other birds!