The retinal circuitry for magnetoreception in migratory birds

Night-migratory birds use the Earth’s magnetic field to determine the direction in which they want to migrate. Many studies suggest that this “magnetic compass sense” is light dependent and mediated by blue light sensors, called cryptochromes, which are expressed in the retina of night-migratory birds. In this review, we summarize the evidence that the avian retina processes not only visual information but also magnetic compass information. We also review the current knowledge on cryptochrome expression in the bird retina and highlight open questions which we aim to address within the framework of SFB 1372 Magnetoreception and Navigation in Vertebrates.