A mechanism of compass-free migratory navigation

Abstract

Abstract How migratory birds can find the right way when navigating over thousands of miles is an intriguing question that has greatly interested researchers in both the fields of biology and physics for centuries. There are several putative proposals that sound intuitively plausible; all remain contested so far because these hypothetical models of magnetoreceptors that sense the geomagnetic field need either extremely high sensitivity or humankind-like intelligence to guide. Here we explore theoretically whether birds can navigate to their destination through an entirely new scenario to sense the geomagnetic field. Our proposal is based on separate peaks of the resonance-fluorescence spectrum of a four-level system derived from the ferric sulfide cluster that exists in a MagR/Cry protein complex (Drosophila CG8198) of migratory birds. As the separation of spectral peaks contains information about the geomagnetic field at both the current location and the birthland, the change of such separation cues the bird to choose the right direction to move, and double-resonance emerges once it has arrived at its destination. Our theoretical mechanism can explain previous experiments on the disorientation of migratorybirds caused by oscillating magnetic field naturally and more precisely. This work provides insight into explaining migratory navigation and motivates possible humanmade practical devices.