I hear the first hylodes by chance, but no doubt they have been heard some time.

April 1. 

Sunday. Warm, with the thick haze still concealing the sun. 

Worm-piles abundant this morning. 

Our gooseberry begins to show a little green, but not our currant. 

3 P. M. — Up Assabet in boat. 

There is another fire in the woods this afternoon. It is yet more hazy than before, — about as thick as a fog, and apparently clouds behind it. 

Still warmer than yesterday, — 71 at 3 P. M. 

The river was lowest for March yesterday, viz. just three feet below Hoar's wall. It is so low that the mouths of the musquash-burrows in the banks are exposed with the piles of shells before them. 

Willows about the stump on S. Brown's land are very well out. Are they discolor? 

The red maple buds are considerably expanded, and no doubt make a greater impression of redness. 

A kingfisher seen and heard. 

As we paddle up the Assabet we hear the wood turtles -- the first I have noticed — and painted turtles rustling down the bank into the water, and see where they have travelled over the sand and the mud. This and the previous two days have brought them out in numbers. Also see the sternothærus on the bottom.

The river being so low, we see lines of sawdust perfectly level and parallel to one another on the side of the steep dark bank at the Hemlocks, for thirty rods or more visible at once, reminding you of a coarse chalk line made by snapping a string, not more than half an inch wide much of it, but more true than that would be. The sawdust adheres to the perfectly upright bank and probably marks the standstill or highest water for the time. This level line drawn by Nature is agreeable to behold. 

The large Rana fontinalis sits enjoying the warmth on the muddy shore. I hear the first hylodes by chance, but no doubt they have been heard some time. 

Hear the hum of bees on the maples. 

Rye-fields look green. 

Pickerel dart, and probably have some time. 

The sweet-gale is almost in bloom; say next pleasant day. [It sheds its pollen the same night in my chamber, — from the old mill-site, north side.]

H. D. Thoreau, Journal, April 1, 1860

The red maple buds are considerably expanded, and no doubt make a greater impression of redness. See April 10, 1853 ( "The male red maple buds now show eight or ten (ten counting everything) scales, alternately crosswise, and the pairs successively brighter red or scarlet, which will account for the gradual reddening of their tops. They are about ready to open.")

As we paddle up the Assabet we hear the wood turtles and painted turtles rustling down the bank into the water, This and the previous two days have brought them out in numbers. See  April 1, 1858 ("See wood turtles coupled on their edges at the bottom, where the stream has turned them up.") See also  March 31, 1858 ("The painted and wood turtles have seemed to be out in surprising abundance at an unusually early date this year, but I think I can account for it. The river is remarkably low," ) and A Book of the Seasons, by Henry Thoreau,the Painted Turtle (Emys picta); A Book of the Seasons, by Henry Thoreau, The Wood Turtle (Emys insculpta)

I hear the first hylodes by chance, but no doubt they have been heard some time. See March 23, 1859 ("While reconnoitring there, we hear the peep of one hylodes somewhere in this sheltered recess in the woods."); March 31, 1855 (“I go listening for the croak of the first frog, or peep of a hylodes."); March 31, 1857 (“How gradually and imperceptibly the peep of the hylodes mingles with and swells the volume of sound which makes the voice of awakening nature! If you do not listen carefully for its first note, you probably will not hear it, and, not having heard that, your ears become used to the sound, so that you will hardly notice it at last, however loud and universal."); April 2, 1852 ("I hear a solitary hyla for the first time.")

The river being so low, we see lines of sawdust perfectly level and parallel to one another on the side of the steep dark bank at the Hemlocks. . . .reminding you of a coarse chalk line made by snapping a string, not more than half an inch wide much of it, but more true than that would be. See April 1, 1858 ("The river is at summer level. . . . It is remarkable that the river seems rarely to rise or fall gradually, but rather by fits and starts, and hence the water-lines, as indicated now by the sawdust, are very distinct parallel lines four or five or more inches apart.”) See also November 23, 1853 ("What an engineer this water is! It comes with its unerring level . . . an obvious piece of geometry in nature.") and alao A Book of the Seasons, by Henry Thoreau, at the Leaning Hemlocks.

The large Rana fontinalis sits enjoying the warmth on the muddy shore. See March 22. 1860 ("The yellow-spot turtle and wood turtle, Rana fontinalis, and painted tortoise come forth."); March 24, 1859 ("There sits also on the bank of the ditch a Rana fontinalis, and it is altogether likely they were this species that leaped into a ditch on the 10th. This one is mainly a bronze brown, with a very dark greenish snout, etc., with the raised line down the side of the back. This, methinks, is about the only frog which the marsh hawk could have found hitherto."); April 5, 1858 ("What I call the young bullfrog, about two and a half inches long, — though it has no yellow on throat. It has a bright-golden ring outside of the iris as far as I can see round it. Is this the case with the bullfrog? May it not be a young Rana fontinalis? No yellow to throat.."); See also A Book of Seasons,  by Henry Thoreau, Identifying the Green Frog in Spring.

Hear the hum of bees on the maples. See April 1, 1858 ("The white maples are abundantly out to-day. . . .We hold the boat beneath one, surprised to hear the resounding hum of honey-bees, which are busy about them,"); April 1, 1852 ('' Saw the first bee of the season on the railroad causeway,") See also A Book of the Seasons by Henry Thoreau, White Maple Buds and Flowers

The sweet-gale is almost in bloom; say next pleasant day. See April 22, 1855 ("The blossoms of the sweet-gale are now on fire over the brooks, contorted like caterpillars")