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Abstract

Twice each year, millions of night-migratory songbirds migrate thousands of kilometers. To find their way, they must process and integrate spatiotemporal information from a variety of cues including the Earth’s magnetic field and the night-time starry sky. By using sensory-driven gene expression, we discovered that nightmigratory songbirds possess a tight cluster of brain regions highly active only during night vision. This cluster, here named ‘‘cluster N,’’ is located at the dorsal surface of the brain and is adjacent to a known visual pathway. In contrast, neuronal activation of cluster N was not increased in nonmigratory birds during the night, and it disappeared in migrants when both eyes were covered. We suggest that in night-migratory songbirds cluster N is involved in enhanced night vision, and that it could be integrating visionmediated magnetic andor star compass information for nighttime navigation. Our findings thus represent an anatomical and functional demonstration of a specific night-vision brain area.