he
carried them to school, showed them to the other boys, and told them
where they came from. Then each boy said to himself, 'It will be all
right if I take only one egg from each nest.' But when four or five boys
had each taken one, all the nests were quite empty. So the poor birds
left that man's field, where the bugs and worms grew and throve, till
they ate up his hay and all the rest of his crops.

"When the nesting season is over eggs that have not hatched are often
left in the various nests, that you can take without doing any harm. Of
course I know it is not easy to keep your hands off such pretty things
as birds' eggs; but if by doing so you can be patriotic and useful, it
is an act of self-denial that you will be glad to do for the good of the
country."

"What is in that black case, uncle?" asked Dodo. "Is it a pistol to
shoot birds? I think it looks too fat for that."

"Not the kind of a pistol that you mean, Dodo, but the only kind that
you youngsters need to bring down birds so that you can see them. It is
a double-barrelled gun, but you must use your eyes for bullets, instead
of leaden balls. See!"--and he took a fine pair of field-glasses from
the case, moved the screw a little, and held them before Dodo's
eyes--"what do you see down there in the grass?"

"Why, it's a Robin, but how big it looks! Every feather shows by itself,
and it has white rings round its eyes like spectacles. I never saw them
before, I'm sure."

Then, as the Doctor handed the glasses to Nat, Dodo looked in her lap,
expecting to find the bird there instead of a hundred feet away.

"This is jolly!" cried Nat, taking a peep and passing the glasses to
Rap, who put them to his eyes, gave a little "ah," and looked through
them until the Doctor said, "That will do now. Olive shall keep the
glasses, and whenever you children want them she will give them to you;
but you must be careful never to scratch them or rub your fingers over
the lenses at either end. With this magnifying instrument you will be
able to see the shape of beaks and wings, and many color markings you
would never notice otherwise. But what did I promise to tell you of
to-day, children?"

"Citizen Bird, you said," replied Nat, "though I don't think I quite
know what you mean."

"What does _citizen_ mean?" asked the Doctor, smiling.

"I think it is a person who lives in a city, but birds aren't people and
they don't live much in the city."

"You are right in one se