What Am I?

Clue 1: I am a type of creepy crawly that can fly and hop.

Clue 2: I can make singing sounds with my legs and wings.

Clue 3: A group of me is called a swarm.

Clue 4: I like to live in fields and forests but you will find me in other habitats too.

Clue 5: I can jump very long distances using my 2 very powerful back legs.

Clue 6: I love to eat green food like leaves and grass.