Zebra finches have a light-dependent magnetic compass similar to migratory birds
To investigate how the behavioural responses of birds under different kinds of light match with cryptochromes as the primary magnetoreceptor, we examined the spectral properties of the magnetic compass in a non-migratory songbird, the zebra finch. We trained birds to find a food reward inside a plus-shaped maze, using magnetic compass cues as only source of information. We found that the birds were well-oriented when trained and tested under low-intensity green light (521 nm). In the presence of radio-frequency (RF) electromagnetic noise, the birds were disoriented, which supports the involvement of radical-pair reactions in the primary magnetoreception process. Birds trained and tested under red light (638 nm) showed a weak tendency to orient ~45° clockwise of the trained magnetic direction. Under low-intensity blue light (460 nm), they tended to orient in the correct direction, but were disoriented under higher intensities of light. Zebra finches trained and tested under high-intensities of indigo light (430 nm) were well-oriented, but again disoriented in the presence of an RF-field. We conclude that the magnetic compass responses of zebra finches are similar to those observed in nocturnally migrating birds and agree with cryptochromes as the primary magnetoreceptor, suggesting that light-dependent, radical-pair-mediated magnetoreception is a common property for all birds, including non-migratory species.
To the paper in Journal of Experimental Biology: "Zebra finches have a light-dependent magnetic compass similar to migratory birds"