OCR Text |
Show Migratled MJcration Migration ef 01 of nirdaThere Olras Dlrcbl nirda OlrasThere DlrcblThere There ar Bro arc * many man ) ' theories theorlea conceiu-Ing conceiu Ing concern- concern concerning concerning - - - ing the causes eauses of the fall faU and .prlna prlna spring springmigrations . springmigrations .prlnamigrations migrations of bird birds . This ThIa annual mi- mi ml- ml migration mlgration ml-gratloa ml gratloa - - gration I Is . a definite deftnlte hereditary hab hab- habIt habit habit - - it tha that t recurs In annual cycles cycle . Impelled Im Im- - Impelled Impelled - pelled by some mysterious force force forcethe . , the birds set Bet out upoa upon long Ion . Jour jOUJlo jour- Journeys jOUJloneypoinUng journeyspointing - ney-poinUng ney poinUng neys-pointing neys pointing neys . - - pointing their course unerr- unerr unerringly unerringly unorr-Ingly unorr Ingly - - - ingly over great expanses expanse . of water waterand waterand and land to arrive at their winter winterquarters winterquarters winterquarters quarters or breeding grounds ground . . |