Part 36

Outside New England, where Usnea is scarce, the nests are often built in hanging clusters of twigs of hemlocks or spruces, with the use of more or less of this lichen when available. In the lower Mississippi Valley, Spanish moss (Tillandsia usneoides) offers a popular substitute and is generally found growing in profusion. But some nests are built of various other materials. George H. Stuart, 3d, writes to me of a nest he found at Pocono Lake, Pa., on June 22, 1916: "This remarkable nest was placed in a horizontal limb of a spruce, 20 feet up and 12 feet from the trunk, near the tip and overhanging a road near the lake." It was "composed mainly of fine dry grasses and the thinnest of bark shreds, with a few bits of down, fashioned together oriole-like, though loosely, with a few coarse grasses projecting suggesting the handiwork of the magnolia warbler. The tiny basket was suspended from the under side of the branch, partially supported by inclining twigs. In form it is an inverted cone or pear, measuring 3 inches deep by 3 inches wide at the rim, the thin walls tapering down to a narrow, pointed bottom. The thinness of the walls in places revealed the eggs from a side view."

Mrs. Nice (1931) reports a curious nest, found by Mr. Kirn near Copan, Okla.; it was fastened to ivy leaves and to a stick which was hanging down, held by the vine. "In this hanging, swaying cluster about two feet long, the nest was built almost entirely of box elder blossoms held together by spider webs on the outside, and sycamore seed down on the inside with a light lining of fine strips of weed stems."

Several nests have been reported as built of various materials in bunches of leaves and other rubbish deposited by freshlets on branches over streams.

Because of the bird's habit of using various materials and sites in its nest building, it may be well to mention some nesting records from the southern Gulf States. Andrew Allison wrote to Dr. Chapman (1907):

The invariable nesting site is a clump of Spanish moss--where this it to be had; I have not observed nests from beyond the range of this plant. The nest is generally placed near the branch from which the long filaments of the 'moss' depend, so that it is well concealed. The height from the ground varies from about eight feet upwards. * * * The nest is nearly hemispherical in shape, opening directly upward. The usual material, in lower Louisiana, is thistle down, which is abundant during the nesting season. Animal hairs are not used, I think. A nest from Bay St. Louis was composed of the very black horse-hair-like inner fiber resulting from the decay of Tillandsia.

M. G. Vaiden writes to me that he found a nest near Belzoni, Miss., in a heavy oak swamp where there were clusters of Usnea on practically all of the trees. The nest was 16 feet above the ground and 12 feet out on a limb of an oak; it was made like our northern nests and lined with the "moss" and fine rootlets. Another described in his notes was entirely different. It was in a section of Mississippi where there was no Usnea growing within 60 miles. The nest was 6 feet from the ground and 4 feet out in the crotch of a limb of a hackberry tree. A pretty nest, it was nicely constructed of leaves and bark from cypress trees, and was lined with small rootlets and very fine twigs.

Eggs.--The usual set for the northern parula warbler consists of 4 or 5 eggs; 3 sometimes constitute a full set, and as many as 6 or 7 have been found in a nest; there are 3 sets of 7 in the J. P. Norris collection. The eggs are ovate or short ovate, have only a slight gloss, and are white or creamy white, speckled and spotted with shades of "russet," "chestnut," "bay," and "auburn," with a few underlying spots of "brownish drab." There is much variation; on some eggs the "brownish drab" color is entirely lacking, while on others spots of this color are the most prominent markings; again, the eggs may be almost immaculate, or may have just a few indistinct freckles of "pale wood brown" at the large end. The measurements of 50 eggs average 16.5 by 12.1 millimeters; the eggs showing the four extremes measure =18.3= by 12.7, 16.9 by =12.9=, =14.8= by 11.9, and 16.3 by =11.2= millimeters (Harris).

Young.--The period of incubation does not seem to have been determined, nor do we know how long the young remain in the nest. Incubation of the eggs and brooding of the young is performed mainly by the female, but the male assists in both to some extent. I have seen a male leave a nest in which there were eggs; and Mr. Mousley (1924) saw a male brood the young for a period of 4 minutes in the absence of the female, but he left as soon as she returned. Both parents feed the young. Mr. Mousley's table shows that during a watching period of 15 hours the male fed the young 45 times and the female fed them only 21 times; the average rate of feeding was once in 13.6 minutes; during this time the male brooded once and the female 34 times, a total of 11 hours and 27 minutes. He "noticed that the food the male brought consisted almost invariably of soft green larvae, whereas, that of the female more often than not consisted of insects, and the portions she brought were usually smaller in proportion than those of her partner."

Plumages.--Dr. Dwight (1900) says that the natal down is "smoke-gray." The sexes are alike in the juvenal plumage, which Ridgway (1902) describes as "above plain slate-gray, slightly tinged with olive-green; middle and greater wing-coverts narrowly tipped with white; chin and upper throat pale yellowish; lower throat, chest, sides, and flanks plain light gray (intermediate between mouse gray and gray no. 6); abdomen, anal region, and under tail-coverts white; remiges and rectrices as in adults."

A postjuvenal molt, involving all the contour plumage and the wing coverts but not the rest of the wings or the tail, begins about the middle of July. This produces a first winter plumage in which old and young birds are very much alike and the sexes are recognizable. The young male differs little from the adult male, but the bluish gray of the upper parts is more heavily tinged with olive-green, the yellow of the under parts is duller, and the dark throat band is more or less obscured by yellowish tips on the feathers. The young female differs from the adult female in a similar way and is without any brown throat band.

Dr. Dwight (1900) says that the first nuptial plumage is "acquired by a partial prenuptial moult which involves chiefly the head, chin and throat, but not the rest of the body plumage, the wings nor the tail. The ashy blue crown feathers faintly dusky centrally, the blackish ones of the sides of the head with a white spot above and below the eye and the yellow or chestnut-tinged chin feathers as far as the pectoral band or farther are assumed by moult. Wear brings the back into contrast with the nape and whitens the lower parts. The wings and tail are browner and more worn than in the adult, especially the primary coverts."

A first postnuptial molt in July and early August, which is complete, produces the fully adult plumage. Fall males are similar to spring males, but the blue areas are more or less tipped with greenish and the throat bands with yellowish. Fall females differ in the same way from the spring birds, and there is little, if any, chestnut and no blackish in the throat band.

Subsequent molts and plumages are the same as described above for the young birds.

Charles C. Ayres, Jr., writes to me of a bird he observed near Ottumwa, Iowa: "It was a typical parula warbler with the exception that the blue-gray color extended over the throat and terminated abruptly on the upper breast. Immediately below the termination of the blue-gray color was the well-defined orange-brown breast band, below which the rest of the breast was yellow."

Food.--The parula warbler is almost wholly insectivorous. Its food is mainly obtained in the deciduous trees, where it is often seen among the branches and twigs or hanging downward under a cluster of leaves or blossoms like a chickadee searching for small insects, beetles, flies, moths, larvae, and egg clusters. Some flying insects are taken on the wing; and occasionally the bird may be seen feeding on the ground.

Dr. Wetmore (1916) reports on the contents of 61 stomachs from Porto Rico, which contained 97.7 percent animal matter and only 2.3 percent vegetable matter. The latter "consisted of seeds of small berries of the camacey (Miconia prasina) and others." In the animal food, beneficial insects and a large number of spiders amounted to about 35 percent, and the remainder were all harmful pests. "Lantern flies (Fulgoridae) (19.09 percent) were identified in 29 stomachs. * * * Other bugs (3.69 percent) comprise small numbers of leaf bugs, species of the chinch bug family, stink-bugs, and a few predaceous assassin bugs. The birds are fond of beetles, and this order supplies 22.53 percent of the food, nearly all being injurious species. Ladybird beetles (1.36 percent) were present in 14 stomachs. Longicorn beetles (1.68 percent) were taken 11 times, and leaf beetles of several species (7.95 percent) were eaten by 30 of these birds." Other beetles taken included darkling beetles, skin beetles, scarred-snout weevils, coffee leaf-weevils, stalk borers, and curculios. Among other items were a few ants and other small Hymenoptera (3.57 percent) and flies (1.19 percent). Caterpillars were found in 18 stomachs and moths in 4. Spiders (29.53 percent) were identified in 29 stomachs. Stuart T. Danforth (1925), from Puerto Rico, adds berries of Varronia angustifolia and fleabeetles, and says that large moth eggs were eaten by two birds, forming 25 percent of their food. Forbush (1929) says that "it feeds much on small hairless inch-worms, such as the fall canker-worm and the spring canker-worm, and on the younger and smaller hairy caterpillars, such as the gipsy and the tent caterpillar."

Behavior.--The parula warbler is less active in its movements, more sedate and deliberate, than most of the other tree-top wood warblers.

It creeps along the branches and hops from twig to twig, often clinging to the under side of a cluster like a chickadee, an action that led some of the early writers to refer to it as a small titmouse, and it sometimes clings to the trunk of a tree like a nuthatch in its search for food. The birds are fearless and confiding, and are easily approached. Even when their nest is disturbed they come within a few feet of the intruder, making little, if any, protest or demonstration. George B. Sennett (1878) tells the following story, illustrating the confiding nature of the bird:

Just before we sighted land, imagine our surprise and joy to see a little Blue Yellow-backed Warbler on our mast. It soon flew down to the sail and thence to the deck, where, after a few moments, it felt quite at home. Our sailor caught him, and he was passed around for all to admire and pet. It would nestle in our hands and enjoy the warmth without the least fear. When allowed his freedom, he would hop upon us, fly from one to another, and dart off over the side of the boat as if taking his departure; when lo! back he would come with a fly or moth he had seen over the water and had captured. Several flies were caught in this way. He searched over the whole boat and into the hold for insects. Often he would fly to one or the other of us, as we were lying on the deck, and into our hands and faces, with the utmost familiarity. He received our undivided attention, but could have been no happier than we. Upon reaching shore, amid the confusion of landing we lost sight forever of our pretty friend.

Voice.--The parula warbler has a simple, but to my ears a very distinctive, song. In 1900 I recorded the song in my notes as "pree-e-e-e-e-e-e, yip, a somewhat prolonged trill like a pine warbler's, but fainter and more insect-like, ending abruptly in the short yip with a decided emphasis." I have always been able to recognize it by the explosive ending, which I never heard from any other wood warbler.

Gerald Thayer wrote to Dr. Chapman (1907) as follows:

The Parula is weak-voiced, and its call notes, as far as I know, are slight and barely peculiar; but it has at least three main songs, with great range of variations.

All may be recognized, or at least distinguished from the weak songs of the Dendroicae, like the Blackburnian and Bay-breast, by their beady, buzzy tones. In phrasing, in everything but tone-quality, certain variations of the Parula's and of the Blackburnian's songs very nearly meet and overlap; but the tell-tale tones remain unchanged,--wheezy and beady in the one, smooth as glass in the other. Commonest of the Northern Parula's three main songs is probably the short, unbroken buzz, uttered on an evenly-ascending scale, and ending abruptly, with a slight accentuation of the final note. Next is that which begins with several notes of the same beady character, but clearly separated, and finishes, likewise on an ascending scale, with a brief congested buzz. The third main song is based on an inversion of the second--a buzz followed by a few separate drawled notes, high-pitched like the buzz-ending of the two other songs. All these vary and intervary perplexingly.

Aretas A. Saunders contributes the following notes on the song of this warbler: "The parula warbler has two distinct types of song. One is a simple buzzy trill rising in pitch, and frequently terminated by a short, sharp note of lower pitch. Of 12 records of this song, 7 have the terminal note and 5 do not. The other form has the same buzz-like quality, but begins with three or four short notes on the same pitch, followed by a longer, higher note that is frequently, but not always, slurred upward. Both songs are similar in length and in pitch intervals. They vary from 1-1/5 to 1-3/5 seconds in length. The rise in pitch varies from one to four and a half tones, and averages about two tones. The actual pitch is exceedingly variable in individuals and varies from A´´´ to D´´´´´. Songs vary considerably in loudness, many of them becoming suddenly louder toward the end.

"The species sings throughout migration, and on the breeding grounds till late July. At that season I have seen males still singing while feeding young just out of the nest."

Enemies.--Dr. Friedmann (1929) writes; "This bird is practically free from that greatest enemy of most of the warblers, the Cowbird. Occasionally, however, parasitic eggs are found in the dainty pensile nests of the Parula Warbler. Stone found a nest on May 26, 1892, at Cape May Point, New Jersey, containing three eggs of the Warbler and one of the Cowbird. * * * Five other records have come to my notice, from Long Island, New York, Pennsylvania and Connecticut, and the bird is listed as a victim of the Cowbird by several writers, as Bendire, Davie, and Chapman." Mrs. Nice (1931) records two more cases in Oklahoma.

Harold S. Peters (1936) records two lice, Myrsidea incerta (Kellogg) and Ricinius sp., as external parasites on this species.

Field marks.--The parula, is one of our smallest warblers. The adult male is well marked, with its blue upper parts, the yellow back being inconspicuous, two conspicuous white wing bands, black lores, yellow breast and chestnut or blackish throat band. The female is duller in all colors, more greenish above and has little or no throat band. Young birds are even less conspicuously marked, as noted in the description of plumages.