Now is the very time to tap birches of all kinds.

April 11. 

8.30 A. M. — To Tarbell’s to get black and canoe birch sap. 

Going up the railroad, I see a male and female rusty grackle alight on an oak near me, the latter apparently a flaxen brown, with a black tail. She looks like a different species of bird. Wilson had heard only a tchuck from the grackle, but this male, who was courting his mate, broke into incipient warbles, like a bubble burst as soon as it came to the surface, it was so aerated: Its air would not be fixed long enough. 

Saw a kingfisher on a tree over the water. Does not its arrival mark some new movement in its finny prey? He is the bright buoy that betrays it!

And hear in the old place, the pitch pine grove on the bank by the river, the pleasant ringing note of the pine warbler. Its  a-che, vitter vitter, vitter vitter, vitter vitter, vitter vitter, vet rings through the open pine grove very rapidly. I also heard it at the old place by the railroad, as I came along. It is remarkable that I have so often heard it first in these two localities, i.e. where the railroad skirts the north edge of a small swamp densely filled with tall old white pines and a few white oaks, and in a young grove composed wholly of pitch pines on the otherwise bare, very high and level bank of the Assabet. When the season is advanced enough, I am pretty sure to hear its ringing note in both those places. 

The hazel sheds pollen to-day; some elsewhere possibly yesterday. 

The sallow up railroad will, if it is pleasant, to-morrow. 

When I cut or break white pine twigs now, the turpentine exudes copiously from the bark, even from twigs broken off in the fall and now freshly broken, clear as water, or crystal. How early did it? 

Set two spouts in a canoe birch fifteen inches in diameter, and two in a black birch two feet plus in diameter. The canoe birch sap flowed rather the fastest. 

I have now got four kinds of birch sap. That of the white birch is a little tinged brown, apparently by the bark; the others are colorless as water. I am struck by the coolness of the sap, though the weather may be warm. Like wild apples, it must be tasted in the fields, and then it has a very slightly sweetish and acid taste, and cool as iced water. 

I do not think I could distinguish the different kinds of birch with my eyes shut. I drank some of the black birch wine with my dinner for the name of it; but, as a steady drink, it is only to be recommended to outdoor men and foresters. 

Now is apparently the very time to tap birches of all kinds. I saved a bottleful each of the white, canoe, and black birch sap (the yellow I boiled), and, in twenty-four hours, they had all three acquired a slight brown tinge but the white birch the most brown. They were at first colorless. 

On the whole, I have not observed so much difference in the amount of sap flowing from the six kinds of trees which I have tapped as I have observed between different trees of the same kind, depending on position and size, etc. This flowing of the sap under the dull rinds of the trees is a tide which few suspect. 

Though the snow melted so much sooner on the east side of the railroad causeway than on the west, I notice that it still lies in a broad, deep bank on the east side  of Cheney’s row of arbor-vitae, while the ground is quite bare on the west. Whence this difference?

A few more hylas peep to-day, though it is not so warm as the 9th. These warm pleasant days I see very few ducks about, though the river is high. 

The current of the Assabet is so much swifter, and its channel so much steeper than that of the main stream, that, while a stranger frequently cannot tell which way the latter flows by his eye, you can perceive the declination of the channel of the former within a very short distance, even between one side of a tree and another. You perceive the waters heaped on the upper side of rocks and trees, and even twigs that trail in the stream. 

Saw a pickerel washed up, with a wound near its tail, dead a week at least. Was it killed by a fish hawk? Its oil, when disturbed, smoothed the surface of the water with splendid colors. Thus close ever is the fair to the foul. The iridescent, oily surface. The same object is ugly or beautiful, according to the angle from which you view it. 

Here, also, in the river wreck is the never-failing teazle, telling of the factory above, and sawdust from the mill. The teased river! These I do not notice on the South Branch. 

I hear of one field plowed and harrowed, — George Heywood’s. Frost out there earlier than last year. 

You thread your way amid the rustling oak leaves on some warm hillside sloping to the south, detecting no growth as yet, unless the flower-buds of the amelanchier are somewhat expanded, when, glancing along the dry stems, in the midst of all this dryness, you detect the crimson stigmas of the hazel, like little stars peeping forth, and perchance a few catkins are dangling loosely in the zephyr and sprinkling their pollen on the dry leaves beneath. 

You take your way along the edge of some swamp that has been cleared at the base of some south hillside, where there is sufficient light and air and warmth, but the cold northerly winds are fended off, and there behold the silvery catkins of the sallows, which have already crept along their lusty osiers, more than an inch in length, till they look like silvery wands, though some are more rounded, like bullets. The lower part of some catkins which have lost their bud-scales emit a tempered crimson blush through their down, from the small scales within. The catkins grow longer and larger as you advance into the warmest localities, till at last you discover one catkin in which the reddish anthers are beginning to push from one side near the end, and you know that a little yellow flame will have burst out there by to-morrow, if the day is fair. 

I might have said on the 8th: Behold that little  hemisphere of green in the black and sluggish brook, amid the open alders, sheltered under a russet tussock. It is the cowslips’ forward green. Look narrowly, explore the warmest nooks; here are buds larger yet, showing more yellow, and yonder see two full-blown yellow disks, close to the water’s edge. Methinks they dip into it when the frosty nights come. Have not these been mistaken for dandelions?

Or, on the 9th: This still warm morning paddle your boat into yonder smooth cove, close up under the south edge of that wood which the April flood is bathing, and observe the great mulberry-like catkins of yonder aspen curving over and downward, some an inch or more in length, like great reddish caterpillars covered thickly with down, forced out by heat, and already the sides and ends of some are loose and of a pale straw-color, shedding their pollen. These, for their forwardness, are indebted to the warmth of their position. 

Now for the white maple the same day: Paddle under yonder graceful tree which marks where is the bank of the river, though now it stands in the midst of a flood a quarter of a mile from land; hold fast by one of its trailing twigs, for the stream runs swiftly here. See how the tree is covered with great globular clusters of buds. Are there no anthers nor stigmas to be seen? Look upward to the sunniest side. Steady! When the boat 'has ceased its swaying, do you not see two or three stamens glisten like spears advanced on the sunny side of a cluster? Depend on it, the bees will find it out before noon, far over the flood as it is. 

Seek out some young and lusty-growing alder (as on the 9th), with clear, shining, and speckled bark, in the warmest possible position, perchance where the heat is reflected from some bank or hillside and the water bathes its foot. The scales of the catkins generally are loosened, but on the (sunniest cheek of the clump, be hold one or two far more considerably loosened, wholly or partially dangling and showing their golden insides. Give the most forward of these a chuck, and you will get a few grains of its yellow dust in your hand. Some will be in full bloom above, while their extremities are comparatively dead, as if struck with a palsy in the winter. Soon will come a rude wind and shake their pollen copiously over the water.

H. D. Thoreau, Journal, April 11, 1856

Now is apparently the very time to tap birches of all kinds. See A Book of the Seasons, by Henry Thoreau, Birches in Season

[A] stranger frequently cannot tell which way the [main channel] flows . . . See April 16, 1852 ("Many a foreigner who has come to this town has worked for years on its banks without discovering which way the river runs.")

The teased river!. . .   See April 2, 1853 ("Together with the driftwood on the shore of the Assabet and the sawdust from Heywood's mill, I pick up teasel-heads from the factory with the wool still in them. How many tales the stream tells!”)

Saw a kingfisher on a tree over the water. See April 1, 1860 ("A kingfisher seen and heard");April 10, 1859 ("See a kingfisher flying very low, in the ricochet manner, across the water."); April 15, 1855 ("See and hear a kingfisher—do they not come with the smooth waters of April? — hurrying over the meadow as if on urgent business.”); April 17, 1858 ("See several kingfishers"); April 22, 1855 ("The bluish band on the breast of the kingfisher leaves the pure white beneath in the form of a heart"); April 23, 1854 (“A kingfisher with his crack, — cr-r-r-rack.”); April 24, 1854 ("The kingfisher flies with a crack cr-r-r-ack and a limping or flitting flight from tree to tree before us ”) ; April 30, 1857 ("Hear a kingfisher at Goose Pond.")

The pleasant ringing note of the pine warbler . . . See April 9 1856 ("the edge of the great pines and oaks in the swamp by the railroad . . .its simple, rapidly iterated, cool-sounding notes.. . . sound particularly cool and inspiring, like a part of the evergreen forest itself, the trickling of the sap."); April 2, 1853("--vetter vetter vetter vetter vet, -- the cool woodland sound")  A Book of the Seasons,   the Pine Warbler.