I will give few points;
- birds like hens, ducks,...(poultry) are useful to humans because of their meat and eggs.
- birds like crows and scavengers clen the environment in which we live.
- birds like pigeons were usefulto humans in the ancient times to delivers messages on warfields and between nations.
- birds like owls,...etc. prove to be help full to the farmers and others by catching rats,mice and other pests including beetle, rice weevils and other insects.