Page 92 - Das Wunder der Migration bei Tieren
P. 92
Left: The struc tu re of the
mag ne tic fi eld re semb les
that of a coil. Its ef fect is
stron gest at the po les and
we akens to wards the equ -
ator. So me birds ha ve be en
fo und to sen se this fi eld,
who se exis ten ce pe op le ha ve
dis co ve red only re cently.
But birds ha ve per ce ived
this ef fect for mil li ons of ye -
ars and can ea sily de ter mi ne
which way to go when mig -
ra ting.
90
