They take in oxygen and exhale carbon-monoxide. Instead, birds have beaks which they use to crush and tear food. There are as many different kinds of beaks as there are birds. Birds also grind up their food with muscles in their stomach called a gizzard . Birds store food in their crop which is a pouch in their throat.
Birds eat berries, seeds, insects and some even eat worms.
Big birds such as vultures and hawks will swoop down to the ground and grab small rodents with their sharp beaks. Since they eat other animals and plants, birds are consider omnivorous . Birds live in the fields or in the woods. Some birds build nests out of twigs and grasses. Other birds live in hollowed out places in trees.