of the little
Indians who had once gathered wampum shells from the same beach in the
long ago. They were wiser also in many ways, for they had found out many
things for themselves--which is the very best sort of wisdom. Now even
Dodo could tell by the footprints on the sand whether a three-toed
Plover or a four-toed Sandpiper had been pattering there.

[Illustration: Hooded Merganser.]

When the right day came, without a sign of ugly squalls or of an
equally unfortunate calm, Olaf borrowed a largo cat-boat, and after
stowing away the lunch hamper, that was always a 'must be' for an
all-day trip, the boat almost flew out of the little bay and up the
sound before the breeze that came with the morning tide.

"There are some more of your white Crows, Nat," said the Doctor, as they
headed straight out after getting on the right tack. "The island where
we are going is one of their famous nesting places."

"Their wings are very different from Crows' wings," said Rap, as he
watched them overhead, now winnowing the air with steady wing-beats, or
circling on motionless pinions--now poising in one spot for a minute by
merely flapping the wings, and then dropping gracefully to float on the
water. "Gulls' wings bend out more at the tip and are smooth-edged;
Crows' look flatter and are saw-edged."

"Are there any other birds besides Gulls that nest on the island, Uncle
Roy?" asked Nat.

"Yes, the Terns or Sea Swallows that you have seen about the reef nest
there also; and this island, as well as the mainland near by, is a
favorite stopping-place for all the shore and water birds in their
journeys,--from Sandpipers to great flocks of Sea Ducks."

"I should think it would be a long swim for Ducks," said Nat; "it is as
much as fifteen miles from shore."

"They don't swim--they fly there," said Olaf.

"Can Ducks fly?" exclaimed Dodo in amazement. "I'm sure the white Ducks
at the Farm can only waddle on the ground, or swim and spatter along the
water when Wolf or Quick chases them for fun. And anyway their legs are
very stiff and queer and grow very far back, as if their bodies were too
heavy and going to fall down front, and they had to hold up their heads
very high to keep going."

"Our tame Ducks are very fat and lazy, for they have lived in captivity
for many generations; yet they could fly very well with a little
practice. The Mallard, which is a wild River Duck and a swift enduring
flyer, is the one which has been domes