The leafy season: departure of the warblers

June 4.

I notice to-day that most maple, birch, willow, alder, and elm leaves are fully expanded, but most oaks and hickories, ash trees, etc., are not quite. You may say that now, the leafy season has fairly commenced.

Most trees now hold out many little twigs with two or three fully expanded leaves on it, between us and the sun, making already a grateful but thin shade, like a coarse sieve, so open that we see the fluttering of each leaf in its shadow.

About a month ago, after the strong and cold winds of March and April and the (in common years) rain and high water, the ducks, etc., left us for the north. 

Now there is a similar departure of the warblers, on the expansion of the leaves and advent of yet warmer weather. The black-poll warblers (Sylvia striata) appear to have left, and some other warblers, if not generally, with this first clear and bright and warm, peculiarly June weather, immediately after the May rain.

Their season with us, i. e. those that go further, is when the buds are bursting, till the leaves are about expanded; and probably they follow these phenomena northward till they get to their breeding-places, flying from tree to tree, i. e. to the next tree which contains their insect prey.

In a week or more the twigs will have so extended themselves, and the number of fully expanded leaves be so increased, that the trees will look heavy and dark with foliage and the shadow be dark and opaque, - a gelid shade. Hazy, and mountains concealed.

H. D. Thoreau, Journal, June 4,1860

The leafy season has fairly commenced.  See May 27, 1853 ("A new season has commenced - summer - leafy June.”); December 30, 1855 ("Winter now first fairly commenced, I feel. ")

. . .like a coarse sieve, so open that we see the fluttering of each leaf in its shadow. See June 2, 1854 (" I would fain be present at the birth of shadow") and June 2 ,1860 ("not yet heavy masses of verdure, but a light openwork, the leaves being few and small yet, as regularly open as a sieve.")

The black-poll warblers (Sylvia striata) appear to have left. . . See JJ Audubon ("Abundantly found in the State of New Jersey close to the sea-shore, the Black-poll Warbler are met with in groups of ten, twelve, or more, in the end of April, but after that period few are to be seen. In Massachusetts they begin to appear nearly a month later, the intervening time being no doubt spent on their passage through New York and Connecticut. I found them at the end of May in the eastern part of Maine, and met with them wherever we landed on our voyage to Labrador, where they arrive from the 1st to the 10th of June, throwing themselves into every valley covered by those thickets, which they prefer for their breeding places.")

June 4. Leave off flannel. Yesterday and to-day uncomfortably warm when walking. 

The foliage of the elms over the street impresses me as dense and heavy already, — comparatively. 

The black-poll warblers (Sylvia striata) appear to have left, and some other warblers, if not generally, with this first clear and bright and warm, peculiarly June weather, immediately after the May rain. About a month ago, after the strong and cold winds of March and April and the (in common years) rain and high water, the ducks, etc., left us for the north. 

Now there is a similar departure of the warblers, on the expansion of the leaves and advent of yet warmer weather. Their season with us, i. e. those that go further, is when the buds are bursting, till the leaves are about expanded; and probably they follow these phenomena north ward till they get to their breeding-places, flying from tree to tree, i. e. to the next tree which contains their insect prey.  

p.m.- To Fair Haven Hill. They began to carry round ice about the 1st. What I called Carex conoidea in '59, was seen June 2d this year in fruit, and may have flowered with C. pallescens. C. Hubbard's first meadow, south side of Swamp Brook willows. Glyceria fluitans, say two or three days, Depot Brook. I see the great blue devil's-needles coasting along the river now, and coupled. Carex retrorsa (much of it going to seed), Hubbard's Bath shore, say ten days. Has the general aspect of pallescens. At Staples Meadow I observe that a great deal of the pitcher-plant is quite dry, dead, and slate-colored, with some green flower-buds pushing up, perhaps. I think it was thus half killed by the drought of April and May. The clear brightness of June was well represented yesterday by the buttercups (Ranunculus bulbosus) along the roadside. Their yellow so glossy and varnished within ; but not without. Surely there is no reason why the new butter should not be yellow now. The time has come now when the laborers, having washed and put on their best suits, walk into the fields on the Sabbath, and lie on the ground at rest. Aphides on alders, which dirty your clothes with their wool as you walk. 

A catbird has her nest in our grove. We cast out strips of white cotton cloth, all of which she picked up and used. I saw a bird flying across the street with so long a strip of cloth, or the like, the other day, and so slowly, that at first I thought it was a little boy's kite with a long tail. 

The catbird sings less now, while its mate is sitting, or maybe taking care of her young, and probably this is the case with robins and birds generally. 

At the west spring of Fair Haven Hill I cast a bit of wood against a pitch pine in bloom (perhaps not yet in prime generally), and I see the yellow pollen-dust blown away from it in a faint cloud, distinctly for three rods at least, and gradually rising all the while (rising five or six feet perhaps). 

I hear that the nest of that marsh hawk which we saw on the 29th (q. v.) has since been found with five eggs in it. So that bird (male), whose mate was killed on the 16th of May, has since got a new mate and five eggs laid. 

One asks me to-day when it is that the leaves are fully expanded, so that the trees and woods look dark and heavy with leaves. I answered that there were leaves on many if not on most trees already fully expanded, but that there were not many on a tree, the shoots having grown only some three inches, but by and by they will have grown a foot or two and there will be ten times as many leaves. 

Each tree (or most trees) now holds out many little twigs, some three inches long, with two or three fully expanded leaves on it, between us and the sun, making already a grateful but thin shade, like a coarse sieve, so open that we see the fluttering of each leaf in its shadow; but in a week or more the twigs will have so extended themselves, and the number of fully expanded leaves be so increased, that the trees will look heavy and dark with foliage and the shadow be dark and opaque, — a gelid shade.

Hazy, and mountains concealed. 

I notice to-day, for example, that most maple, birch, willow, alder, and elm leaves are fully expanded, but most oaks and hickories, ash trees, etc., are not quite. You may say that now, when most trees have fully expanded leaves and the black ash fairly shows green, the leafy season has fairly commenced. (I see that I so called it May 31 and 27, 1853.)