Part 14

_Voice._--Samuel F. Rathbun (MS.) gives me his impression of the song of the lutescent warbler as follows: "Its song is a succession of trilling notes on a slightly rising then falling key, the latter more lightly given and faster. There is an apparent ease in this song that is suggestive of airiness, and, although simple in construction, it is pleasing to hear and further bears the stamp of distinctiveness."

_Fall._--The fall migration is southward to southern California, western Mexico, and Guatemala. The movement is apparently leisurely and quite prolonged, for the earliest birds begin leaving western Washington in August and September, and Theed Pearse gives me two October dates for Vancouver Island, with his latest date November 1. Taylor and Shaw (1927) write of the fall movement on Mount Rainier as follows:

The postnuptial scatter movement was in full swing by the middle of August. At this time the lutescent warbler was often found in the same flocks with Shufeldt juncos, western golden-crowned kinglets, or chestnut-backed chickadees. It is not unlikely that there is some good reason for this flocking, aside from the companionship involved. The warblers and the juncos, kinglets, or chickadees probably do not compete for food as would one warbler with another of the same species. The individual warbler, attached to a flock of kinglets, let us say, may be the more surely guided to available food. Then, too, differences in alertness of the two or more species concerned may afford greater protection to each than would be the case if they remained separate.

Robert Ridgway (1877) met with these warblers in large numbers in Nevada:

In the fall, the thickets and lower shrubbery along the streams, particularly those of the lower cañons, would fairly swarm with them during the early portion of the mornings, as they busily sought their food, in company with various insectivorous birds, especially the Black-capped Green Warbler (_Myiodioctes pusillus_) and Swainson's Vireo (_Vireosylvia swainsoni_). At such times they uttered frequently their sharp note of chip. The brightly-colored specimens representing _H. lutescens_ were prevalent in the western depression of the Basin, but were not observed eastward of the upper portion of the Valley of the Humboldt, nor at any locality during the summer; and wherever found, were associated with individuals of the other form, which is the only one found breeding on the mountains. It is therefore inferred that all these individuals were migrants from the northern Pacific Coast region and the Sierra Nevada, while those of _H. celata_ proper were from the higher portions of the more eastern mountains, or from farther northward in the Rocky Mountain ranges, full-fledged young birds being numerous in the high aspen woods of the Wasatch Mountains in July and August.

VERMIVORA CELATA SORDIDA (Townsend)

DUSKY ORANGE-CROWNED WARBLER

PLATE 15

HABITS

The subspecific characters of this warbler, as given by the original describer, C. H. Townsend (1890), are: "Adult male: Entire plumage decidedly darker than _H. celata lutescens_. Feet and bill larger; wings slightly shorter. There is an appearance of grayness about the upper plumage, owing to a leaden tinge on ends of feathers. Throat and under parts slightly streaked."

The principal breeding range of the dusky warbler is on the Santa Barbara Islands off the coast of southern California, but it has also been known to breed in San Diego and probably breeds farther south in Baja California, and on the Todos Santos Islands, off that coast.

The dusky orange-crowned warbler was discovered by Dr. Townsend on San Clemente Island January 25, 1889, but it does not seem to be so common there as on some of the other islands. According to A. Brazier Howell (1917) it has been reported from all of the channel islands except San Nicholas, which is too barren for it; and its occurrence on Santa Barbara Island is doubtful, as this precipitous island is not suited for it. It is probably commonest on Santa Catalina Island, "in the darker canyons and on the wooded hillsides."

J. Stuart Rowley writes to me: "I found that the weekend nearest the 15th of April was the ideal time to hunt nests of this warbler on Catalina Island, and after much hiking about this island I finally located a little ravine, only about a mile or so out of the town of Avalon, where these warblers nested abundantly, due to the little trickle of surface water in the bottom of the ravine. Since most of the ravines here are dry, this one was 'made to order' and I enjoyed the chance to find many nests in the short time allotted to me. Around the middle of April this little ravine fairly trilled with the songs of many males, who were constantly pursuing trespassing individuals out of their nesting territories, only to return and continue their melodic songs."

_Nesting._--Of its nesting habits, J. Stuart Rowley continues: "I have found dusky warblers nesting in every conceivable sort of place, ranging from those placed on the ground in the grass to those placed 15 feet up in toyon trees. The usual nesting site here seems to be in a small toyon bush, rather well concealed, but not over 2 to 3 feet from the ground; the nests are made of fibres and grasses and, although nicely cupped and lined, are rather bulky affairs externally for a warbler to build." Howell (1917) writes:

The usual nesting site of the Lutescent Warbler is on the ground, but I have never heard of _sordida_ building in such a situation. On the smaller barren islands, such as the Coronados and Todos Santos (where it is common), they build in a bush or tangle of vines, a foot or so above the ground, and the nest is always mainly constructed of gray moss, where this is to be had, lined with a little fine grass. On the larger islands, where there are good-sized trees, the site chosen may be a thicket of vines several feet above the bed of a stream, a small shrub, say four feet up, or perhaps an oak as much as fifteen feet above the ground. In such case the nest is quite substantially made of leaves, twigs, bark, rootlets, and often a little sheep wool. Three or four eggs constitute a set, and at least two broods of young are raised each year.

A most unusual nesting site for a dusky warbler is described by Clinton G. Abbott (1926). It was--

a decorative fern basket inside a small lath house adjoining the home of Mrs. A. P. Johnson, Jr., at 2470 C Street, San Diego. * * * Her house is in one of the older residential sections of the city, known as Golden Hill. The homes here are large and surrounded by more or less extensive grounds, but the whole aspect is distinctly urban, with streets everywhere paved. Broadway, with double trolley tracks, is only one block away. The lath house, sixteen by twenty-four feet in size, was filled with a luxuriant growth of cultivated plants. A rectangular path within was marked at its corners by four wire fern baskets suspended about four feet from the ground. In one of these were the remains of the two previous years' nests, and in the basket diagonally opposite was the inhabited nest, which contained three eggs. Although the eggs were manifestly not fresh, there was no bird about and they seemed cool to my touch. I waited about for fully ten minutes and was beginning to fear that disaster had overtaken the home, when I heard a low, scolding note overhead. Then down from between the slats hopped the dainty little warbler, and, with no concern whatsoever, she took her place upon the eggs, although I was standing in full view close by. [The nest was] cosily placed in the moss at the base of the ferns.

We soon discovered that not only was the bird practically fearless in the ordinary sense, but that she would even allow us to touch her without leaving her nest. She would permit us to raise her from her eggs with no greater protest than a pecking at the intruding finger. If she was not sitting sufficiently broadside for a good photograph, it was possible to arrange her the way we wanted her! Sometimes, if our familiarity was beyond her patience, she would merely hop among the foliage behind the nest, wait there for a few minutes, and then nestle back on her eggs.

_Eggs._--Three eggs seem to constitute the average set for the dusky warbler, with occasionally only two or as many as four. Mr. Rowley tells me that, out of at least two dozen nests examined, he found only two sets of four; one nest had only one newly hatched young, and two or three nests held two well-incubated eggs. The eggs are apparently indistinguishable from those of the mainland races. The measurements of 27 eggs average 17.0 by 13.2 millimeters; the eggs showing the four extremes measure =18.5= by 13.5, 17.6 by =14.0=, and =16.0= by =12.7= millimeters.

_Winter._--Many of the dusky warblers, perhaps most of them, desert the islands in the fall when they become dry and uninviting, for the winter spreading widely on the mainland as far north as the San Francisco Bay region and inland to Merced County. Dr. Joseph Grinnell (1898) says: "This subspecies appears in the vicinity of Pasadena in the oak regions and along the arroyos in large numbers during August, and even by the middle of July. Remains in diminishing numbers through the winter; the latest specimen noted in the spring was secured by me, Feb. 29 ('96)."

VERMIVORA RUFICAPILLA RUFICAPILLA (Wilson)

EASTERN NASHVILLE WARBLER

PLATES 16, 17

HABITS

Alexander Wilson discovered this species near Nashville, Tenn., and gave it the name Nashville warbler. Baird, Brewer, and Ridgway (1874) say of its early history: "For a long while our older naturalists regarded it as a very rare species, and knew nothing as to its habits or distribution. Wilson, who first met with it in 1811, never found more than three specimens, which he procured near Nashville, Tenn. Audubon only met with three or four, and these he obtained in Louisiana and Kentucky. These and a few others in Titian Peale's collection, supposed to have been obtained in Pennsylvania, were all he ever saw. Mr. Nuttall at first regarded it as very rare, and as a Southern species."

This is not strange when we stop to consider that this bird is more or less irregular in its occurrence, apparently fluctuating in numbers in different localities and perhaps choosing different routes of migration. Its record here in eastern Massachusetts illustrates this point. Thomas Nuttall never saw the bird while he lived in Cambridge, from 1825 to 1834. Dr. Samuel Cabot, who lived there from 1832 to 1836, told William Brewster (1906) that he was sure that it did not occur regularly in eastern Massachusetts at that time. According to Brewster:

Soon afterwards a few birds began to appear every season. They increased in numbers, gradually but steadily, until they had become so common that in 1842 he obtained ten specimens in the course of a single morning.

In 1868, and for some fifteen years later, I found Nashville Warblers breeding rather numerously in Waltham, Lexington, Arlington and Belmont, usually in dry and somewhat barren tracts sparsely covered with gray birches, oaks or red cedars, or with scattered pitch pines. A few birds continue to occupy certain of these stations, but in all of the towns just mentioned the Nashville Warbler is less common and decidedly less generally distributed in summer now than it was twenty-five or thirty years ago.

Forbush (1929) found it "more common in eastern Massachusetts in the latter quarter of the last century than it is today." And my own experience has been similar; prior to 1900 we used to consider the Nashville Warbler a common bird on migrations and even found it breeding in Bristol County in 1892; but we have seen very little of it since the turn of the century.

_Spring._--From its winter home in Mexico and Central America, the eastern Nashville warbler seems to migrate mainly northeastward through Texas to the lower Mississippi Valley and then west of the Alleghenies to New England and northward up the central valleys. Some individuals apparently fly straight across the Gulf of Mexico, but it is very rare in Louisiana, for which Dr. Oberholser (1938) gives only three records. It seems to be very rare, or entirely unknown, in any of the southeastern States, east of Louisiana and south of Virginia, except in some of the mountains.

According to Dr. Chapman's (1907) tables, about 18 days elapse between the average date of the first arrival of the species in Missouri and that of its first appearance in Minnesota, and it seems to require exactly the same time to migrate from West Virginia to New Brunswick.

Dr. Dayton Stoner (1932) says of its migration through the Oneida Lake region, N. Y.:

The Nashville warbler here seems to prefer coppices along the edges of woodland such as young aspen and maple and elm thickets and other small growth that springs up in cut-over and burned-over areas. In such situations I have found it singing persistently in late May and the first few days in June. This warbler and the chestnut-sided are often found together. However, it does not confine its activities to thickets, for it not infrequently visits woodlands of tall elm, maple, beech and other deciduous trees, as well as mixed forest and the vegetation in door-yards. The flowering currant is in full bloom at the time this bird reaches the height of its abundance and I have seen it visiting such shrubbery during the first part of May.

In Massachusetts in May, according to Forbush (1929), "among its favorite haunts are the bushy edges of woodlands, whether along roads, railroads or streams, or about ponds, lakes, marshes, swamps or open fields. It may often be found among willows, alders, birches or poplars. Old neglected fields and pastures, with scattered growths of birches and bushes, are favorite feeding grounds, but the bird also visits orchards, gardens and shade trees, even in city parks. It may be found on dry lands where scattered pitch pines grow, and on moist lands with rank shrubbery."

W. E. Clyde Todd (1940) says of the migration in western Pennsylvania: "The Nashville Warbler appears during the flood tide of the warbler migration in both spring and fall and is sometimes inordinately abundant. * * *

"Almost every spring there is a day or two of decided movement, when the species is very common and on occasion exceedingly abundant. On May 3, 1901, I witnessed a remarkable flight at Beaver. That morning the woods everywhere were full of Nashville warblers, to the exclusion of almost all other kinds. I counted a dozen in one tree. They kept mostly in the treetops and were singing very little."

These warblers are also sometimes abundant in Ohio, for Milton B. Trautman (1940) noted as many as 80 individuals on May 15, 1932, at Buckeye Lake.

_Nesting._--The nesting haunts of the eastern Nashville warbler are quite varied, and habitats similar to some of those frequented on the spring migration seem to be suitable for breeding grounds. But the nest is always placed on the ground and generally is well hidden. Gerald Thayer wrote to Dr. Chapman (1907):

Birch Warbler would be a good name for this bird as it appears in the Monadnock region where it breeds abundantly. For here it is nowhere so common as in abandoned fields and mountain pastures half smothered by small gray birches. From the airy upper story of these low and often dense birch copses the Nashvilles sing; and among the club-mosses and ferns, and the hardhacks and other scrubby brushes at their bases and around their borders, the Nashvilles build their nests. But such is merely their most characteristic home. * * * Dark spruce woods they do not favor, nor big, mixed virgin timber; but even in these places, one is likely to find them wherever there is a little "oasis" of sunlight and smaller deciduous growth. They are fairly common among the scanty spruces, mountain ashes, and white birches of the rocky ridge of Mt. Monadnock, almost to the top--3,169 feet.

F. H. Kennard records in his notes two nests found near Lancaster, N.H. One was among some dead weeds on a mossy hummock in a pasture; the other was in a swamp, at the base of and under a clump of alders beside a path. Miss Cordelia J. Stanwood (1910), of Ellsworth, Maine, writes:

When a growth of evergreens--pine, fir, spruce and hemlock--is cut, it is succeeded by a growth of hard wood--gray, white and yellow birches, maple, poplar, beech, cherry and larch--and vice versa. As the woodland is cut in strips, there are always these growths in juxtaposition. Though the nest of the Nashville is always placed among the gray birches, the inevitable strip of evergreen woodland is near at hand, and a swale not far away.

The nest of the Nashville is sometimes placed in comparatively low ground (that is, compared with its immediate surroundings), in soft green moss under an apology for a shrub, again in the side of a knoll covered with bird wheat (hair-cap) moss, or at other times in an open space in the woodlands under a stump, or tent-like mass of grass, or a clump of gray birch saplings. Around the top is usually woven a rim of coarse, soft, green moss; sometimes dried boulder fern or bracken is added. The side coming against the stump or overhanging moss lacks this foundation. The nest is lined with fine hay, if it abounds in the neighborhood, or pine needles if they are nearer at hand. Sometimes both are used. The red fruit stems of bird wheat moss and rabbit's hair are often employed. One or two birds have preferred some black, hair-like vegetable fibre for lining matter, one bird, horse hair.

Ora W. Knight (1908) mentions a Maine nest that "was situated on the ground on an open wooded hillside at the foot of and between two small spruce trees, and was well imbedded in the moss. It measures in depth outside one and three-fourths inches, and inside one inch, the diameter outside was three and a quarter. * * * Nest building begins soon after the birds have arrived, and presumably the female does most of the work, while the male perches in a near by sapling and sings. * * * It takes from seven to nine days to build the nest, and on its completion an egg is laid each day until the set is completed. The eggs are usually laid between six and ten in the morning."

A nest found by Henry Mousley (1918) near Hatley, Quebec, "was located at the foot of a spirea bush on a little mound, well sunk into the surrounding hair-cap moss (_Polytrichum commune_) and dwarf cornel or bunchberry (_Cornus canadensis_) of which the mound was carpeted. It was entirely hidden from sight and would never have been found had I not flushed the female from her set of five eggs."

The only local nest of which we have any record was found by Owen Durfee (MS.) in Rehoboth, Mass., on June 2, 1892. It was only partially concealed among some very low bushes, grass, and other herbage near the foot of a small hill in neglected pasture land; the hill had a scattered growth of oak and beech saplings and had been tramped over by cattle.

Frank A. Pitelka (1940a) found the Nashville warbler breeding in northeastern Illinois in "oak-maple-hickory climax woodland with semi-dense undergrowth, * * * with the stream cutting it and a semi-swampy, sedge-grass area with willow thickets and scattered elms and ashes." In northern Michigan, he found it "in spruce and cedar bogs and in sandy woods of aspen, birch, and Norway pine."

Richard C. Harlow tells me that most of the nests he has found in New Brunswick, about 10, are very frail, but are lined with moose hair. He has found 7 nests in the mountains of Pennsylvania, where the normal lining is deer hair.

_Eggs._--The first set of eggs for the Nashville warbler seems to be always either 4 or 5; reported sets of 3 are probably incomplete or late sets. The eggs are ovate or short ovate and are only slightly lustrous. They are white or creamy white, speckled with shades of reddish brown, such as "chestnut" and "auburn," mixed with "light brownish drab." On some eggs the markings are fairly evenly scattered over the entire surface, but usually they are concentrated and form a wreath at the large end. Occasionally eggs are more boldly marked with spots and small blotches or short scrawls; others are nearly immaculate. The measurements of 50 eggs average 15.7 by 12.1 millimeters; the eggs showing the four extremes measure =17.2= by 12.7, 16.4 by =13.0=, =14.5= by 11.6, and 15.2 by =11.5= millimeters (Harris).

_Young._--The period of incubation is said to be from 11 to 12 days, and probably the female does most of it, though Mr. Knight (1908) says: "One bird relieves the other on the nest and at times when the eggs are very near the hatching point I have seen the male bring insects to its mate on the nest. Possibly he may feed the female at earlier stages of incubation but I have not seen him do so. Both birds feed the young, giving them at first soft grubs and caterpillars, later on small beetles, flies and similar insects. * * * The young leave about the eleventh day after hatching."

For a further study of the nesting behavior of the Nashville warbler, the reader is referred, to an excellent paper on the subject by Louise de Kiriline Lawrence (1948).

_Plumages._--Dr. Dwight (1900) calls the natal down "sepia-brown," and describes the juvenal plumage of the Nashville warbler as follows:

"Pileum hair-brown, back darker, olive tinged, and rump olive-green. Below, pale yellowish wood-brown, straw-yellow on abdomen and crissum. Wings and tail olive-brown broadly edged with bright olive-green, the median and greater coverts tipped with pale buff-yellow forming two wing bands. Lores and auriculars mouse-gray, the orbital ring pale buff."

The sexes are alike in juvenal plumage. A postjuvenal molt occurs in July and August that involves the contour plumage and the wing coverts but not the rest of the wings or the tail. This produces a first winter plumage in which young birds become practically indistinguishable from adults in many cases, but the chestnut crown patch is generally smaller and more veiled in the younger male and is often lacking in the young female.

Dr. Dwight (1900) says that the first nuptial plumage is "acquired by a partial prenuptial moult which involves chiefly the crown, sides of head and throat, but not the rest of the body plumage nor the wings and tail. The head becomes plumbeous gray, the edgings only half concealing the rich chestnut of the crown. The orbital ring is white and conspicuous. Wear is marked, bringing the gray of the nape into contrast with the greenish back, later exposing the chestnut of the crown."

A complete postnuptial molt in July and August produces the fully adult plumage. In fresh fall plumage the head is browner than in spring, the back is grayer, the crown patch is more veiled with gray tips, and the breast is tinged with brownish. The females are paler than the males, with less chestnut in the crown. Adults probably have a partial prenuptial molt similar to that of young birds.

_Food._--Very little has been published on the food of the Nashville warbler. Knight (1908) says that "the food of the adults consists of beetles, larvae of various insects and the eggs of various insects. In fact they eat almost anything which they can glean in the insect line from the shrubbery and ground."

Forbush (1929) says: "As the bird ranges from the ground to the tree-tops it takes most of the insects that any warbler will eat, among them flies, young grasshoppers and locusts, leaf-hoppers and many plant-lice, caterpillars both hairless and hairy, among them the gipsy, brown-tail and tent caterpillar, most of which are taken when young and small; also small wood-boring beetles are eaten, and other small insects of many species. The bird appears to be almost wholly insectivorous."