Show I MOU- MOU MOUNTAINS AFFECT BIRD LIFE Andes Said to Be Responsible for Number Number Num Num- ber of Species Found In South America The richness of South American blyd b life bird Ilfe Is due to the presence of lit the A Andes more than to any ens other one 11 thin thing It Is la the absence of great n mountain chains In Africa which accounts ac ae- counts for the comparatively small n numbers of ot species of birds s In that c continent From base buse to summit four tour distinct zones of life Ute tropical tropical subtropical sub sub- t tropical temperate and alpine are alpine are found In the higher Andes and each zone has hns species which are confined t to it It is Is not only the height of ot the Andes Andes An An- Andes des which affects bird life lite In places for tor hundreds of ot miles this gigantic range may appear as two or three chains each not less than or feet In n height an and these climatic cli die climatic matic matle walls are re as Impassable to toy the species In the tropical or subtropical subtropical subtropical sub sub- tropical valJe valleys s they as though they extended to the zenith Isolation Isolation Isola Isola- tion Is therefore added to the factors tae fad tors tors' of ot climate and In Inthe Inthe Inthe the making of ot the specIes specie and the three combined have produced a greater great great- er variety of ot bird life lite than Is found In any area of ot similar extent In the world The American museum of ot natural natural nat nat- ural nral history inaugurated In to 1911 a biological biological biological bi bi- survey of ot the Andean region with particular reference to Its Ito b bird ird life As a result of ot the collections and field studies made the museum Is now In possession of large collections I and data t from om the more northern north north- I ern em part of ot the chain i I r 1 |