Life Histories of North American Wood Warblers, Part One and Part Two. Arthur Cleveland Bent

Life Histories of North American Wood Warblers, Part One and Part Two - Arthur Cleveland Bent


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been taken, so far as I can learn, but few times in the western part of the State; it seems to be more common in the eastern, where it breeds.” He cites the first record of the finding of a nest in the State in 1869. There is, however, an earlier record of its nesting. Dr. Brewer (1874) states: “Dr. Samuel Cabot was the first naturalist to meet with the nest and eggs of this bird. This was in May, 1837, in Greenbrier County, Va.”

      William Brewster (1906), speaking of the bird in 1874, when he first found it in eastern Massachusetts, says: “If the species inhabited any part of the Cambridge Region before the year just mentioned, it was overlooked by several keen and diligent collectors, among whom may be mentioned Mr. H. W. Henshaw and Mr. Ruthven Deane.” Since that time the bird has increased in numbers here until at present it is common in suitable localities.

      Spring.—The goldenwing appears in eastern Massachusetts about the middle of May, or sometimes a little earlier, at the time when many of the resident warblers are arriving on their breeding-grounds. At this season the bright green leaves are beginning to open in the thickets and trees on the borders of woodlands where the goldenwing finds its food; and under the trees in the wooded swamps where the bird will build its nest, fresh new growth—skunkcabbage, ferns, and a host of spring plants—is pushing through the dead leaves, spreading a green carpet on the forest floor. But even thus early in the year, when the trees are nearly bare, it is not easy to see as it feeds high up in the trees, far out near the tips of the branches. Indeed, but for its queer little song, we should rarely suspect that it had come back to its summer home.

      Nesting.—The golden-winged warbler builds its nest on the ground, generally raised somewhat by a substratum of dead leaves. The nest is supported by stalks of herbs—often goldenrod or meadow rue—or by fern fronds, or it may be hidden deep in a clump of grass, or it may lean against the base of a small shrub or tree with grass all about it. The leaves above the nest develop as the season advances and soon completely conceal it, and the plants, by their growth, may raise the nest a little above the ground. The cup of the nest is made chiefly of long strands of dry grass and narrow strips of grapevine bark, with a few hairs in the lining. This fine, flexible material is pressed down on the inside by the weight of the incubating bird and the nestlings, becoming smooth and firm like a mat, whereas on the outside wall the long grass blades and fibrous vegetable shreds are left free and, protruding loosely in all directions for some distance from the cup, produce a disorderly, unkempt appearance, like a little loose handful of fine hay.

      Edward H. Forbush (1929) quotes an account of the goldenwing by Horace O. Green who has had an extensive experience with the species and who gives the following interesting details of the construction of the nest:

      The nest of the Golden-wing usually has a bottom layer of coarse dead leaves on which is placed a ring of large dry leaves, arranged with the points of the leaves downward, so that the leaf stems stick up noticeably around the edges of the nest proper, which is built within and upon this circular mass of leaves, and is made of rather wide strips of coarse grass or rushes, and usually has considerable grape vine bark interwoven in it. The nest lining is coarse and rough, sometimes the eggs being laid on the rough grape vine bark, and in some nests other coarse fibers are used. A very characteristic feature of the nest lining is fine shreds of light reddish-brown vegetable fiber, which at first glance might easily be mistaken for dry needles from the pitch pine—but careful examination shows it to be the inner layers of the bark from the grape vines. The nest is very bulky for the size of the bird and Is rather loosely put together by crossing the materials diagonally, so that it slightly resembles a rather coarse basket-work. I never saw a nest of this species which had a soft lining, such as many other warblers use—the eggs are apparently always deposited on rough material.

      The general color of the nest is very dark, especially just after a rain, when the materials of which it is composed look almost black—this being one thing which helps to distinguish these nests from those of the Maryland Yellow-throat, which generally builds a much lighter colored nest, lined with fine grass, and sometimes with horse hair. Another small point of difference which is noticeable on close examination is that the lining in the Yellow-throat’s nest is usually of a much finer and lighter colored material, and appears to be woven in horizontally, or at least to show some traces of such a design, especially around the upper edge—while the Golden-wing closely adheres to the diagonal criss-cross pattern with the loose ends of the nesting materials sticking up at an angle above the rim of the nest cavity.

      Mr. Green describes the surroundings of the nest thus:

      For their summer home these birds prefer the border of deciduous woods, where tall trees give plenty of shade, to an adjacent clearing with a growth of briers, bushes and grass, and the nest is usually placed just outside the line of the forest proper, but within the shade of the trees. A meadow wholly surrounded by woods is frequently selected. The ideal place to search for a nest of the species is in one of those woodland meadows, which has a clear brook flowing through it, with briers, tussocks of grass and a fresh growth of goldenrod scattered around in profusion, with birch trees and wild grape vines growing near the edges where the meadow meets higher ground—and all this bordered by tall oak, chestnut and maple trees which furnish an abundance of shade to the vegetation of the meadow itself.

      J. Warren Jacobs (1904) describes the nest much as above and adds: “The opening is not straight down, but slightly tilted, the jaggy leaf-stems and bark sometimes reaching two or three inches above the rim of the nest proper. As incubation advances, the rough rim on the lower edge of the nest becomes broken down, and by the time the young birds are ready to leave, this part of their home is worn smooth by the attendant parents.”

      He gives the measurements of 17 nests as follows: “Outside 3.6 to 5.0 inches in diameter, and 3.0 to 5.0 inches in depth; and on the inside, from 1.7 to 2.5 inches in diameter by 1.3 to 2.5 inches deep.” These measurements agree very closely with the records of several other observers. Jacobs continues: “Seemingly before the birds have had time to complete their nest, the female begins the deposition of the eggs. Generally, where I had opportunity to watch the nests daily, or at intervals between the beginning and completion of the set, the eggs were laid on consecutive days, but in two or three instances it was noticed that the laying missed a day.”

      Eggs.—The set for the golden-winged warbler may consist of anywhere from 4 to 7 eggs; 5 is perhaps the commonest number, but 4 is a common number, and the larger numbers are increasingly rare. The eggs are ovate or short ovate, and have only a slight luster. They are white or creamy white, with a wide variety of markings in “auburn,” “argus brown,” “Mars brown,” “hazel,” “Hay’s brown,” “liver brown,” and “burnt umber,” with underlying speckles or spots of “light brownish drab” and “light vinaceous drab.” There is, also, much variation in the amount of markings, some being very sparingly speckled and others are quite heavily marked, with some of the spots assuming the proportions of blotches. Occasionally small hairline scrawls, or scattered spots, of brown so dark as to appear almost black, are found. The markings are usually denser toward the large end. The measurements of 50 eggs average 16.7 by 13.0 millimeters; the eggs showing the four extremes measure 18.6 by 13.0, 16.8 by 13.7, 15.5 by 12.5, and 15.9 by 12.3 millimeters (Harris).

      Young.—Jacobs (1904) states that the incubation period is 10 days and that the young birds are able to leave the nest 10 days after hatching. In a nest which Maunsell S. Crosby (1912) watched closely, the eggs hatched on June 1 and the young flew on June 10.

      The fledglings are delicate little birds, brownish olive on the back, washed with yellow below, and have two widely separated yellow wing bars. They have astonishingly long legs and soon become very active, fluttering about in the shrubbery and clinging to the branches. Walter Faxon (1911) in speaking of them gives this lively picture which could well be applied to them soon after leaving the nest: “In appearance and habit they were grotesque little fellows, clinging with their disproportionately long legs to the low herbage, like peeping Hylas in the springtime clinging to the grasses and weeds above the surface of the water. The little thread-like natal plumes still waving from the tips of their crown feathers enhanced the oddity of their appearance.” Mr. Faxon, to be exact, is speaking here of some young birds of mixed parentage,


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