
The SciencesJuly 1, 1957
The Geography of Birds
Although they are free to fly wherever they please, few birds are cosmopolitan. After 150 million years of evolution in a constantly changing environment, most species are confined to provincial abodes

The Geography of Birds
Although they are free to fly wherever they please, few birds are cosmopolitan. After 150 million years of evolution in a constantly changing environment, most species are confined to provincial abodes

Birds as Flying Machines
A sequel to the article on the aerodynamics of birds in the April, 1952, issue of this magazine. Among the remarkable adaptations birds have made to life in the air are high power and light weight