A flock of great egrets waiting for fish to come upstream

At Kubo Weir, I witnessed the great egrets that flew away (7:49). When I followed those great egrets, there were 35 birds downstream of Miyashita Bridge (8:13). There was no noticeable movement for a while. The birds caught the Haya that had run up all at once (8:31). The birds were catching fish for about 4 minutes. The birds can no longer catch fish. Shortly after, the birds began to move to the other side of the bridge (8:37). After catching the fish for a while, the birds returned to their original downstream side (8:44).
It is said that great egrets waiting for fishes to come upstream can be seen only at this time.