He knew that that feat can be performed only by those hawks whose tails are full and not forked, as the bald eagle, and the species already named--their spreading tails giving them the power to suddenly arrest the downward motion, and prevent them from dashing themselves against the earth.

The kites, on the other hand, have not that power; and in this arrangement Lucien could perceive a beautiful adaptation of Nature--an equalising of advantages between these two kinds of birds.

He reasoned thus:-- The hawks, although swift of wing, and capable of extended flight, cannot remain long in the air.

They grow weary and need rest, which they take, perching themselves upon some tree.

It may be observed, moreover, that they choose dead trees that overlook an open space.