Circadian migration is where birds utilize circadian rhythm (CR) to regulate migration in both the fall and the spring. In circadian migration clocks of both circadian (daily) and circannual (annual) patterns are utilized to determine the birds’ orientation in both time and space as they migrate from one destination to the next. This type of migration is advantageous in birds that during the winter remain close to the equator, and also allows the monitoring of the auditory and spatial memory of the birds’ brain to remember an optimal site of migration. These birds also have timing mechanisms that provide avians with the distance required to travel in order to reach their destination. To regulate the migration patterns of these birds, the mammalian circadian clock is utilized. This clock allows birds to determine when the appropriate time is to migrate, which location will best help them regulate their metabolism, and whether land or water travel will be most advantageous.