Quantum effects in magnetoreception

Sustained Quantum Coherence and Entanglement in the Avian Compass.
Erik M. Gauger, Elisabeth Rieper, John J. L. Morton, Simon C. Benjamin, and Vlatko Vedral
Phys. Rev. Lett. 106, 040503 (2011)

According to the RP model, the back of the bird’s eye contains numerous molecules for magnetoreception. These molecules give rise to a pattern, discernible to the bird, which indicates the orientation of the field.