Marine birds are equally at home on land, in the air, and in the water. While many organisms can go from land to water (amphibians, some reptiles, some insects), others generally live in only one medium during their lives. Marine birds switch from one to the other, often daily. Such flexibility requires unique physiological and morphological adaptations to the environment, a medium that has also exerted selective forces on the behavior, ecology, and demography of these birds. Amazingly, marine birds have adapted to essentially all environments on the earth, from those able to survive winters in Antarctica to those who can sit for days incubating their.
