Answer: The four important group of birds are 1. Game Birds 2. Preying Birds, 3. Perching Birds and 4. Flightless Birds.
Game birds are good runners but they cannot fly long distances. Their wings are short and round, but legs are massive. The beaks are also strongly built. Males are aggressive. One male maintains a group of 3-4 females. Game birds include partridges, pheasants, quail, grouse and pea fowls.
Preying birds are predators. They kill mice and other smaller animals and eat them. They have very strong, hook-like beak. There feet have curved and pointed claw. Their vision is very sharp. Preying birds include vultures, kites eagles and falcons.
Perching birds constitute the largest group of birds. When they sit on a tree, their digit grasp the branch of the tree in such a way that they cannot fall off the branch. Baya, larks, swallow, bulbul, finches, house sparrow, weaver-bird, crow and magpie are some common perching birds.
Flightless birds can run but they cannot fly. Flightless birds are large-sized. They generally lack tail feathers. The keel of sternum is absent. Flightless birds include ostriches, rhea, emu, kiwi, and penguin. Ostrich is the largest living bird. It weighs about 157 kg. Ostriches are very good runners. They are found in Africa and Arabia. Rhea is found in South America. It is smaller than ostrich. Emu is found in Australia. It is smaller than rhea. Kiwi is found in New Zealand. It is Southern hemisphere (Antarctica). Their body is suited for diving and swimming.
--Cited From Preserve Articles