Five grey heron chicks were ringed by GPS/GSM bird trackers at Taihu National Wetland Park of Heilongjiang Province in June 2018. Three grey heron chicks died at the beginning of the dispersion, so only two grey heron chicks successfully completed the natal dispersion. Therefore, in the same year, the grey heron chicks numbered NEFU-03 and NEFU-04 respectively, were monitored at different times for their activity distance, activity area, flight speed, flight height, range of activity, etc. The two grey heron chicks flied out of the nests during the early dispersion period, and the average activity area per day was 0.06367 km2 and 0.0599 km2 respectively. The average activity distance per day was 0.7706 km and 0.7987 km respectively. The flight speed was 38 km/h and 12.6 km/h respectively, and the maximum flight height was 224m and 545 m respectively. The grey heron chicks left their nests during the medium dispersion period and the average activity area per day was 220.6683 km2 and 9.1174 km2, respectively. The average activity distance per day is 25.06846 km and12.8771 km respectively. The flight speed was 50.6 and 123 m/h, and the maximum flight height was 215 and 525 m. During the late dispersion period, the average activity area per day was 4.2989 km2 and 14.2428 km2, respectively. The average activity distance per day is 9.2322 km and 5.744 km respectively. The flight speed was 46.7 km/h and 51.5 km/h, and the maximum flight height was 46.7 km/h and 51.5 km/h. The result showed that the activity area, activity distance, flight height, and activity time for grey heron chicks increased with the day age.
