Birds have different types of beaks due to evolution, which has ensured that birds have beaks which are best suited to getting the food that they need.
For example, the saddlebill bird has a very long, sharp beak which is red, yellow and black. It stabs water animals, so this type of beak is required.
Eagles and other birds of prey tear flesh using both their beak and their talons or claws and so they have very sharp beaks. Waxwings on the other hand eat berries, so their beaks are more adapted to clasping tiny berries.
A bird has no teeth, so its beak is very important to assist with feeding. However, a lot of the 'chewing' is actually done within the second part of the bird's stomach, which is commonly known as the 'gizzard'. Some birds actually swallow small pebbles or grit to assist the gizzard in breaking down the food.
Because they eat different things
Well, Birds are not all the same. They're different depending on their living habitat. Where they live and eat. Most Tropical birds are fish & seaweed eaters so their peak straight while some are short and others are long. Frigate birds have a downturn peak which people from my country explain its nature in a legend of the birds. Once, long ago, birds were friendly with each other and soon they plan a get-together party. Before the party was over, they all had a swim. Each bird put away its peak in a secret place. The Frigate bird however, forgot to hide its peak and found out later that it was stolen and was replaced by a turned-peak......Anyway, I think you get the point now.....
Each bird has a beak appropriate for it's lifestyle like the cuved beak of parrots used for crushing nuts, a storks arrow beak for grabbing fish and small creatures and an eagles hooked beak for tearing flesh
As they don't have teeth, they use beak as their mouth and even their nostrils are found on their beaks. So they should have a beak to get their food to assist with feeding etc.
Birds have different types of beaks to make their homes
Each of the birds has its very own beak cause its lifestyle