As predators at the tops of food webs, birds of prey (raptors) are influenced by many factors and processes within nature. Like the caged canary used by miners to detect poisonous gases, birds of prey have proven sensitive to many forms of environmental change, including chemical pollution, and can provide an early warning for humans . This makes them excellent subjects to study for understanding ecological processes and environmental health. Eagles and other large raptors typically require large natural areas for survival. Measures that conserve birds of prey frequently provide an umbrella of protection for entire ecological communities. Increasingly, evidence suggests especially large predators, such as forest eagles, help maintain the balance of nature.