The mystery behind how birds navigate might finally be solved: it’s not the iron in their beaks providing a magnetic compass, but a protein in their eyes that lets them “see” Earth’s magnetic fields.
These findings come courtesy of two papers - one studying robins, the other zebra finches.
The fancy eye protein is called Cry4, and it’s part of a class of proteins called cryptochromes - photoreceptors sensitive to blue light, found in both plants and animals. These proteins play a role in regulating circadian rhythms.
https://www.sciencealert.com/birds-see-magnetic-fields-cryptochrome-cry4-photoreceptor-2018
origin - https://www.pipiscrew.com/2018/09/birds-can-see-earths-magnetic-fields/ birds-can-see-earths-magnetic-fields