US Geological Survey


Date of this Version



Published in The Auk, 89: 766-788, October 1972.


Reasonably accurate measurements of breeding bird populations on large land areas are needed if the overall effects of man's impact on the environment are to be measured and understood. Through use of these data, we will be able to detect the average response of these populations to generalized environmental changes caused by diverse and widespread land-use practices. As this kind of information becomes available, it will serve as the basis for developing appropriate management programs for the purpose of maintaining or increasing breeding bird populations.