Birds mostly use their keen eyesight to find food. They use their beak and their claws to get bugs , worms , small mammals , fish , fruit , grain, or nectar . Birds play a very important part in the natural control of insects and in the dispersal of seeds. Some birds, like the tiny, nectar-eating hummingbird are important pollinators of some flowering plants . Birds bear their young in hard-shelled eggs which hatch after some time.
Birds build nests for breeding in trees, on cliffs, or on the ground.
Most birds are taken care of by at least one parent until they are able to fly and get their own food. The incubation period of bird eggs varies from species to species. There's also some variability due to the temperature. Some birds, like cuckoos and some cowbirds, lay their eggs in other bird's nests. The non-related adult bird takes care of the cuckoo's egg unwittingly.