You want 'collective nouns'. Collective nouns are different for each species. For most birds you can use the generic 'flock' tho each has its own collective as well. Murder of ravens Ballet of swans Badling of ducks Etc - http://collectivenoun.com/
Groups of animals are named according to their type. The terms herds and flocks are used to name animals like cats, dogs and cattle among others that mainly walk on four. A large number of birds is referred to as a pack or flock.
There are different collective nouns depending on he animal in question. Some random examples are: humans - tribe owls - parliament lions - pride snakes - pit rattlesnakes - rumba There you go, that's English for you.