Many species breed in colonies or large communities which is known as communal breeding. It is common to see large groups of these species during their breeding seasons. These breeding colonies and their location are generally protected by wildlife conservation laws. This is to keep the species from going extinct. Some species have evolved to communal breeding in large breeding colonies. They cannot breed in smaller numbers or pairs alone. These species can be threatened by extinction if they are hunted on their breeding grounds or if their breeding colonies are destroyed. The Passenger pigeon is a famous example. They were probably the most numerous land bird on the American continent which had evolved for communal breeding. They became extinct due to large scale hunting in its communal breeding grounds. They were not able to breed in smaller numbers.