INTRODUCTION 



The changing picture of bird populations throughout the year 

 intrigues those who are observant and who wish to know the source 

 and destination of these birds. Birds are the most mobile creatures on 

 Earth. Even man with his many vehicles of locomotion does not equal 

 some birds in mobility. No human population moves each year as far 

 as from the Arctic to the Antarctic and return. Yet the Arctic terns 

 do and without the aid of aircraft or compass. 



Birds are adapted in their body structure, as no other creatures, to 

 life in the air. Their wings, tails, hollow bones, and internal air sacs 

 all contribute to this great faculty. These adaptations make it 

 possible for birds to seek out environments most favorable to their 

 needs at different times of the year. This results in the marvelous 

 phenomenon we know as migration the regular, seasonal 

 movement of entire populations of birds from one geographic 

 location to another. 



Throughout the ages, migratory birds have been important as a 

 source of food after a lean winter and as the harbinger of a change in 

 season. The arrival of certain species has been heralded with 

 appropriate ceremonies in many lands; among the Eskimos and 

 other tribes, the phenomenon to this day is the accepted sign of the 

 imminence of spring, of warmer weather, and a change from winter 

 food shortages. The pioneer fur traders in Alaska and Canada offered 

 rewards to the Indian or Eskimo who saw the first flight of geese in 

 the spring, and all joined in jubilant welcome to the newcomers. 



As the North American Continent became more thickly settled, the 

 large flocks of ducks and geese, rails, doves, and woodcock that 

 always had been hunted for food became objects of the enthusiastic 

 attention of an increasing army of sportsmen. Most of the nongame 

 species were found to be valuable also as allies of the farmer in his 

 never-ending warfare against insect pests. All species have been of 

 ever-increasing recreational and esthetic value for untold numbers 

 of people who enjoy watching birds. We began to realize our 

 migratory bird resource was an international legacy (that cannot be 

 managed alone by one state or country) and all nations were 

 responsible for its well-being. The need for laws protecting game and 

 nongame birds, as well as the necessity to regulate the hunting of 

 diminishing game species, followed as a natural course. In the 

 management of this wildlife resource, it has become obvious that 

 continuous studies must be made of the species' habits, environ- 

 mental needs, and travels. In the United States, the Department of 

 the Interior recognizes the value of this resource and is devoted to 

 programs that will ensure its preservation and wise use. Hence bird 



