"They are small brownish birds with cocked up tails, not at all shy about showing themselves off, when they choose, but they must have some hiding-place to duck into the moment anything frightens them, and some odd, out-of-the-way nook or cranny for their big rubbishy nests.

Some prefer to hide in marshes among the thickest reeds, some live in dry brush heaps, and some, like the Rock Wren, choose piles of stones.

Their wings are not very strong, and they seldom venture far from their favorite retreats, except when they are migrating.
"When your cousin Olive and I were in Colorado we climbed a mountain one day above the timber-line"-- "Do _all_ the trees out there grow in straight lines ?" asked Dodo anxiously.
[Illustration: Rock Wren.] "No, my dear little girl, trees don't grow in straight lines anywhere," said the Doctor, laughing--"except when they are planted so.

The 'timber-line' of a mountain is the edge of the woods, above which no trees grow, and we see nothing but bare rocks, and the few low plants that cling to the cracks among them.

Well, we had hardly rested long enough to get our breath after such a climb, when we heard a rich ringing song, something like a House Wren's, but louder and stronger, and very quick, as if the bird were in a great hurry to get through.