"Teacher, Teacher, Teacher, Teacher, Teacher!"--the accent on the first syllable and each word uttered with increased force and shrillness. No writer with whom I am acquainted gives him credit for more musical ability than is displayed in this strain. Yet in this the half is not told. He has a far rarer song, which he reserves for some nymph whom he meets in the air. Mounting by easy flights to the top of the tallest tree, he launches into the air with a sort of suspended, hovering flight, like certain of the finches, and bursts into a perfect ecstasy of song,--clear, ringing, copious, rivaling the goldfinch's in vivacity, and the linnet's in melody. This strain is one of the rarest bits of bird melody to be heard, and is oftenest indulged in late in the afternoon or after sundown. Over the woods, hid from view, the ecstatic singer warbles his finest strain. In this song you instantly detect his relationship to the water-wagtail,--erroneously called water-thrush,--whose song is likewise a sudden burst, full and ringing, and with a tone of youthful joyousness in it, as if the bird had just had some unexpected good fortune. For nearly two years this strain of the pretty walker was little more than a disembodied voice to me, and I was puzzled by it as Thoreau by his mysterious night-warbler, which, by the way, I suspect was no new bird at all, but one he was otherwise familiar with. The little bird himself seems disposed to keep the matter a secret, and improves every opportunity to repeat before you his shrill, accelerating lay, as if this were quite enough and all he laid claim to. Still, I trust I am betraying no confidence in making the matter public here. I think this is preeminently his love-song, as I hear it oftenest about the mating season. I have caught half-suppressed bursts of it from two males chasing each other with fearful speed through the forest. Turning to the left from the old road, I wander over soft logs and gray yielding debris, across the little trout brook, until I emerge in the overgrown Barkpeeling,--pausing now and then on the way to admire a small, solitary now and then on the way to admire a small, solitary white flower which rises above the moss, with radical, heart-shaped leaves, and a blossom precisely like the liverwort except in color, but which is not put down in my botany,--or to observe the ferns, of which I count six varieties, some gigantic ones nearly shoulder-high.