PROBLEM TO BE SOLVED: To provide an observation system capable of observing a migration of migratory birds in a close state in real time and further observing an abnormal bird by distinguishing the abnormal bird from the other birds.SOLUTION: In a migratory bird observation system including many transmitters 10 attached to each of many migratory birds 12, information processing means 18 for processing information from the many transmitters 10, and reception means 14 for receiving radio waves including the information from the many transmitters 10 and transmitting the radio waves to the information processing means 18, the transmitters 10 are attached to the many migratory birds 12, and transmit triaxial acceleration data of the migratory birds 12 with the transmitters 10 attached thereto.
