FEATURES 



COVER STORY 



28 WILDEBEESTS OF THE SERENGETI 



Migrating in great numbers, the signature antelope 

 of the African savanna must dodge predators, drought, 

 and human development. On the side, 

 it shapes its own habitat. 

 RICHARD D. ESTES 



44 LIVING THE HIGH LIFE 



The mountaintop environment 

 of the Andes harbors a Noah's Ark 

 of previously undocumented species. 

 KEVIN KRAJICK 



PHOTOGRAPHS BY CARSTEN PETER 



36 CHANGE IN THE AIR 



Songbirds with divergent migratory patterns 

 may be a rare example of a hotly debated 

 way of forming a new species. 

 STUART BEARHOP 



41 SONG LINES 



ROBERT B. PAYNE 



AND MICHAEL D. SORENSON 



ON THE COVER: 

 Wildebeests migrate across 

 Tanzania's Serengeti National 

 Photograph by Anup Shah 



•ark. 



