This was amid a thick undergrowth.  Moving on into a passage of large stately hemlocks, with only here and there a small beech or maple rising up into the perennial twilight, I paused to make out a note which was entirely new to me.  It is still in my ear.  Though unmistakably a bird note, it yet suggested the beating of a tiny lambkin.  Presently the birds appeared,—­a pair of the solitary vireo.  They came flitting from point to point, alighting only for a moment at a time, the male silent, but the female uttering this strange, tender note.  It was a rendering into some new sylvan dialect of the human sentiment of maidenly love.  It was really pathetic in its sweetness and childlike confidence and joy.  I soon discovered that the pair were building a nest upon a low branch a few yards from me.  The male flew cautiously to the spot and adjusted something, and the twain moved on, the female calling to her mate at intervals, love-e, love-e, with a cadence and tenderness in the tone that rang in the ear long afterward.  The nest was suspended to the fork of a small branch, as is usual with the vireos, plentifully lined with lichens, and bound and rebound with masses of coarse spider-webs.  There was no attempt at concealment except in the neutral tints, which make it look like a natural growth of the dim, gray woods.

Continuing my random walk, I next paused in a low part of the woods, where the larger trees began to give place to a thick second-growth that covered an old Barkpeeling.  I was standing by a large maple, when a small bird darted quickly away from it, as if it might have come out of a hole near its base.  As the bird paused a few yards from me, and began to chirp uneasily, my curiosity was at once excited.  When I saw it was the female mourning ground warbler, and remembered that the nest of this bird had not yet been seen by any naturalist,—­that not even Dr. Brewer had ever seen the eggs,—­I felt that here was something worth looking for.  So I carefully began the search, exploring inch by inch the ground, the base and roots of the tree, and the various shrubby growths about it, till finding nothing and fearing I might really put my foot in it, I bethought me to withdraw to a distance and after some delay return again, and, thus forewarned, note the exact point from which the bird flew.  This I did, and, returning, had little difficulty in discovering the nest.  It was placed but a few feet from the maple tree, in a bunch of ferns, and about six inches from the ground.  It was quite a massive nest, composed entirely of the stalks and leaves of dry grass, with an inner lining of fine, dark brown roots.  The eggs, three in number, were of light flesh-color, uniformly specked with fine brown specks.  The cavity of the nest was so deep that the back of the sitting bird sank below the edge.

In the top of a tall tree, a short distance farther on, I saw the nest of the red-tailed hawk,—­a large mass of twigs and dry sticks.  The young had flown, but still lingered in the vicinity, and as I approached, the mother bird flew about over me, squealing in a very angry, savage manner.  Tufts of the hair and other indigestible material of the common meadow mouse lay around on the ground beneath the nest.