XIV. Birds of the Water and Birds of the Air
What animals build nests?
And lay eggs in the spring and early summer?
And go in large companies with their mates from one part of the world to another, at certain seasons, following the sun?
And float through the air—as the hawk does when he is sailing?
And fly, as the hawk does, when he "swims" through the air?
"Birds do all these things," you say. So they do. But they are not the only animals that do them. As you know they are not the only animals that lay eggs either. Fish and frogs and snakes lay eggs also. Some fish build nests. Many migrate—going from one part of the water world to another, in the spring or early summer, to lay their eggs.
The fish not only foretells the birds in these habits, but even in their differences in these habits. For, curiously enough, they have different ideas about where to build their nests, just as birds do. Some, like the beautiful little sunfish, that you know so well, lay their eggs on the ground—or beds of rivers—as the meadow-larks do. Others, like the stickle-back, build in the tops of water weeds. Red wing blackbirds build up in cat-tails and rushes.
As if still further to hint that they too are related to our "little brothers of the air," these fish that build nests in little water trees, also guard the eggs. It is only the fish that lay their eggs in the tops of water weeds that are bright enough to guard them. So it will be interesting for you to find, by noticing and inquiring, whether birds that build their nests on the ground are as bright as those that build in bushes or trees. More kinds of enemies get at a nest on the ground. The brighter bird as a rule chooses the better place. But you must not expect to find all birds of the trees wiser than all birds of the ground; for there are the same kind of exceptions among the families of animals as there are among families of men. The meadow-lark is very clever about hiding its ground nest.
And there are fish that fly, just as there are birds that swim. Flying fishes are found in all the warmer waters of the world. It is in the warm countries that many queer animals, that are part one thing and part like another, are found. You know a fish has a pair of fins that he wears on each side of his back in the same place that
