“Do they still nest on Round Island?” asked the Doctor.  “There were a dozen pairs of them there when I was a boy.”

“Yes, sir!  But there is only one pair now.  It’s a great rack of sticks, half as big as a haystack; for they mend it every season, and so it keeps growing until now it is almost ready to fall out of the old tree that holds it.  And, do you know, sir, that Purple Grackles have stuck their own nests into the sides of it, until it is as full of birds as a great summer hotel is of people.”

“Oh, we must see it!” said Olive, who had finished putting her seaweeds to press; “for as yet I have only read about such a nest.”

“What does the Osprey look like near to?” asked Rap.

“Like a large Hawk,” answered the Doctor.  “You would know him to be a Hawk by his hooked beak and claws.  He walks in the procession of bird families along with the cannibal birds among whom he belongs, and who come after the Birds that only Croak and Call.  But he is not a real cannibal, because he lives on fish, and never eats birds.  So I will give you a description of him now.”

The Osprey

Length about two feet.

Upper parts dark brown with some white on the head and neck.

Under parts white with some dark spots.

Feet very large and scaly, with long sharp claws, to hold the slippery fishes he catches.

A Citizen of North America.

A very industrious fisherman who minds his own business and does nobody any harm.

CHAPTER XX

SOME SKY SWEEPERS

About four o’clock, after a long rest, the party started for home, because they wanted to have plenty of time to stop in the wood lane on the way.

The first bird that Nat spied after they left the meadows was perching on the topmost wire of a fence by the roadside.  Every once in a while he darted into the air, snapped up an insect, and returned to the same perch on the wire whence he had started.  He was a very smart-looking bird, with a flaming crest that he raised and lowered to suit himself; and every time he flew into the air he cried “Kyrie—­kyrie!”

“That is a Kingbird,” said the Doctor; “it is very kind of him to show himself, for he is the bird I most wished to see.  We have finished with the true song birds now, and the next order is that of the Songless Perching Birds—­birds that have call-notes, some of them quite musical, but no true song.  So we will name them the Birds that only Croak and Call.

“The crowing of a Rooster, the screech of a Night Owl, the Hawk’s harsh scream, the laughing and hammering of a Woodpecker, all answer the same good purpose as a song.

“The first family of Songless Perching Birds is that of the Tyrant Flycatchers, and the first of these birds with which we have to do is the one you have just seen.  He belongs to the guild of Sky Sweepers.