“Pewee, pewee, pe-e-er!” cried the nest owner very sadly.

“We are going home, so you needn’t worry, dear,” said Dodo.  “Good-night.”

CHAPTER XXII

TWO WINGED MYSTERIES

THE NIGHTHAWK

The sun was quite low when the party drove out of the lane; the birds were singing their very best, and Olive stopped the horses on top of the next hill, that they might all look at the beautiful twilight picture around them.

“How quickly the sun slides when it once begins to go!” said Nat.  “It looks as if it were going into a cage with the striped clouds for bars.”

“Shirk—­shirk—­boom!” A large bird that had been sailing about overhead dropped through the air till it was almost over the surrey, then turned suddenly and darted upward again.

“What is that?” cried Nat and Dodo.

“That’s a Nighthawk—­don’t you remember the bird we heard early one morning in the river woods?  He’s looking for small birds to eat,” answered Rap.

“He is called the Nighthawk, but never eats anything except beetles, flies, and other insects,” said the Doctor, “for he is not a real Hawk.  He takes his name from the fact that he dashes about at twilight and in cloudy weather like a Hawk; but his broad, shallow mouth is only suitable for insect-eating, like his cousin’s, the Chimney Swift’s, and the beak is equally small and feeble, not at all like the strong hooked one of a cannibal bird.  Look overhead!”

“There are two light spots like holes through his wings,” said Rap.  “Ah yes! now I remember about him—­we can always tell him from a real Hawk.”

“How does he make that queer noise?” asked Nat.  “It sounds like when I hit the telegraph wires with stones, or blow in the bunghole of a barrel.”

[Illustration:  Nighthawk.]

“Watch him when he drops,” said the Doctor; “do you not see that he does so with open wings?  The air rushes between the long wing-quills and makes the vibrating noise.  Now he is up and away again, but you see he keeps circling in the sky.”

“Does he build in chimneys?” asked Dodo.

“The Nighthawk does not build any nest; the eggs are laid on bare ground or rock in an open field—­occasionally on a house-top.  Strange as this seems, the parent birds are so near the color of earth and rock that it is very difficult to find them when they are sitting, the young when hatched are equally invisible, and the eggs themselves look like two little stones—­for there are never more than two.  I will show you a Nighthawk in my cabinet, and you will see for yourselves how nicely the colors match ground and rocks.”

“He looks like a pretty big bird,” said Dodo.  “How long is he?  Is there only one in his family?”

“He has a brother called the Whip-poor-will, that we should meet very soon.”