Birds:
* Common birds: Chickens, ducks, geese, pigeons, sparrows, robins, crows, etc.
* Waterfowl: Ducks, geese, swans, etc.
* Birds of prey: Vultures, hawks, eagles, etc. (These birds may gather in flocks, but they are more often called "kettles".)
Other Animals:
* Sheep: A group of sheep is called a flock.
* Goats: A group of goats is sometimes called a flock.
* Kangaroos: A group of kangaroos is sometimes called a mob or a troop.
* Fish: A school of fish can also be called a flock in some contexts.
Important Note: While the term "flock" is often applied to a large number of animals, it's not always used in a strict scientific sense. The specific name for a group of animals varies by species and context.