We have seen it how the most experienced bird leads the whole team, the one all others follow. The Snowy Egret above became the leader for a few minutes and then the whole team fell apart.
The Snowy Egret isn't big bird but in flight when he spreads his wings he looks big.
I learned recently that a leading bird exists only in our mind. No bird is happy to fly at the head of formation for a long time, because doing so a bird will be unable to save energy for the whole flight. As a result, the other birds become "leaders" for a while.
