When they went into action,万 dais always acted uniformly without any disorder. They depended upon the collective efforts to avoid any harm from the outside world.

But when they moved about, they always moved in groups, depended on one another for survival, and flew and landed together.

The Yidais were slow in reaction. They could not fly very high and seemed clumsy and incapable.

According to legend, there was a kind of birds called "dais" (swallow) on the East China Sea.

When they advanced, no one dared to advance rashly. When they retreated, no one dared to fall behind at will. When they fed, no one dared to scramble to be the first. All their activities were orderly.