In this unedited clip, we see 2 take-off flights, many maneuvering flight (landing, circulating, sideways flight, gliding, fighting for a post), and social behavior of birds. The take-off decision seems to depend on one or two leaders. Once in air, a large group of birds fly collectively in circular motion. This coherent structure is not uniform, and contains many internal modes with different time scales. The circulatory motion has a time scale of about 10-20s. The decision for taking off, for following the group, and for switching direction is harder to estimate, but the take-off sequence suggests it to be around a fraction of second. Not all birds prefer to be in a large group. A small group of birds prefers a larger social distance.