Tennessee Warbler

Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.

Bent Life History for the Tennessee Warbler – the common name and sub-species reflect the nomenclature in use at the time the description was written.

Alexander Wilson (1832) discovered this warbler on the banks of the Cumberland River in Tennessee and gave it the common name it has borne ever since, although it seems inappropriate to name a bird for a State so far from its main breeding range in Canada. Only two specimens were ever obtained by him, and he regarded it as a very rare species, possibly a mere wanderer from some other clime, hence the name peregrina. Audubon never saw more than three individuals, migrants in Louisiana and at Key West. And Nuttall, it seems, never saw it at all. Its apparent rarity in those early days was, perhaps, due to the fact that it is inconspicuously colored and might easily be overlooked or mistaken for a small plainly colored vireo or for the more common Nashville warbler; its fluctuation in numbers from year to year in different places may also have suggested its apparent rarity. Here in Massachusetts, we have found it very common in certain years and very scarce in others.

Spring: Professor Cooke (1904) says: “In spring migration the Tennessee warbler is rarely found east of the Alleghenies, nor is it so common in the Mississippi Valley as during the fall migration.” And he makes the rather surprising statement that “the Biological Survey has received no notes from the South Atlantic States on the spring migration of the Tennessee warbler, nor from Alabama, Mississippi, or Louisiana, though two birds were seen in April in Cuba and some were taken on the island of Grand Cayman, and the species has been noted several times in spring at Pensacola, Fla.” Yet he gives April 26, 1885, as the date of its arrival at Rising Fawn, Ga. And H. H. Kopman (1905) writes:

In a small lot of warblers sent Andrew Allison. in the spring of 1902, from the lighthouse on Chandeleur Island, off the southeast coast of Louisiana, was a Tennessee Warbler that had struck the lighthouse April 13. While I had some dubious records of the occurrence of the Tennessee Warbler at New Orleans ï in the early part of April, it was not until 1903 that I saw the species, in spring, and then in some numbers, singing, and loitering to a degree that surprised me, for the first of these transients appeared April 20, and the last was noted May 9. They were restricted almost to one spot, a thicket of willows beside a pond in the suburbs of New Orleans. I observed others the latter part of April, 1906.

This warbler seems to be a rare spring migrant through Florida; A. H. Howell (1932) gives seven records, from Key West to Pensacola, in March and April. The few records available seem to indicate that the main migration route is along the eastern coasts of Central America (Dr. Skutch tells me that he sees it both spring and fall in Costa Rica), Mexico, and Texas to the Mississippi Valley, whence it spreads out to reach its wide breeding range. Some birds may reach Florida via Cuba, and we have some evidence that it migrates across the Gulf of Mexico. It is common on the coast of Texas in spring.

Gerald Thayer wrote to Dr. Chapman (1907) that about Monadnock, N. H., the Tennessee warbler is “very rare, and seemingly irregular. It haunts blossoming apple trees, big elms, and roadside copses of mixed deciduous second growth.”

At Buckeye Lake, Ohio, according to Milton B. Trautman (1940), “the daily and seasonal numbers of no warbler species fluctuated as greatly as did those of the Tennessee Warbler. During some spring migrations it was decidedly uncommon, and never more than 5 individuals were recorded in a day nor more than 35 for the spring. During other years as many as 250 individuals (May 16, 1929) were observed in a day, and more than 800 were noted during the migration.

* * * The birds in spring chiefly inhabited the upper half of the taller trees of both upland and lowland wooded areas and also the upper parts of rows or groups of tall trees along the lake shore, streams, and about farmhouses.”

It must have been a very common migrant in Minnesota at one time, for Dr. Roberts (1936) writes:

Formerly, when a]l Warbiers were more abundant than now, the little Tennessee flooded the tree-tops for a week or ten days in such numbers as to equal, if not excel, all other species put together, excepting only the Myrtle. Insignificant In size and inconspicuous in garb, it made up for these shortcomings by numbers and Incessant vocal effort, indifferent performer though it Is. It Is still one of the commonest species. It keeps well up among the topmost branches and moves restlessly abont in search of food, singing meanwhile with little apparent effort and announcing Its passage from one tree-top to another by a succession of sharp little pea p-ycafs that are almost as characteristic to the trained ear as the song itself.

A. D. Henderson, of Belvedere, Alberta, tells me that the Tennessee warbler is probably the most numerous of the warblers which spend the summer in the territory around Belvedere and in the Fort Assiniboine District. It breeds mainly in poplar woods, but I have also found nests in dry muskeg.”

Nesting: Prior to the beginning of the present century very little authentic information on the nesting habits of the Tennessee warbler was available. Professor Cooke (1904) records two sets of eggs taken by one of the parties of the Biological Survey in 1901 at Fort Smith, Mackenzie, of which he says: “These eggs are among the first absolutely authentic specimens known to science.” And Dr. Chapman (1907) remarked: “The Tennessee Warbler awaits a biographer.” Since then, we have learned much about it, mainly through the writings of B. S. Bowdish and P. B. Philipp, who found it breeding abundantly in New Brunswick. In their first paper (1916) they describe the summer haunts and the nesting habits of this warbler as follows:

The region in question is particularly well adapted to the nesting requirements of the Tennessee Warbler, as we noted them during the above period. Extensive lumbering has removed the greater part of the large growth spruce and balsam Umber, which forms the great bum of the forests of this region, leaving areas of small trees, which, in the older clearings, have grown thickly, and to an average height of ten feet. These are interspersed with areas of more or less open, large timber, and others where the second growth has reached little more than the proportions of somewhat scattered shrubbery. The essentially level surface Is frequently scored by slight depressions which form the beds of tiny streams, bordered on either side by boggy ground, dotted with grass tussocks, bushes and small trees, and overspread with a luxuriant growth of moss. Such areas are most numerous in cleared tracts, but not Infrequent in the edges and the more open portions of the woods. These are the summer home-sites of the Tennessee Warbler. * ï *

At the time of our visit to the breeding country, In the middle of June, nest building was completed and full sets of eggs had been laid. Altogether, ten nests were located, all built on the ground in substantially the same general sort of situation, and all but two were found by flushing the bird. The nest is built In the moss, usually in a wet place at the foot of a small bush, and in most cases In woods, somewhat back from the more open part of the clearings. A hollow Is dug in the moss, usually beneath an overhanging bunch of grass. The nest is in nearly every case entirely concealed and it is impossible to see it from any view-point without displacing the overhanging grass. Consequently unless the bird is flushed it would be all but Impossible to find it. The outer foundation of the nest is of dry grass forming quite a substantial structure. Several nests had whisps of grass stems extending from the front rim, as noted In description of the first nest below. It is lined, usually, with fine dry grass, to which in some instances the quill-like hairs of the porcupine, or white moose hairs, are added, and more rarely still, fine hair-like roots which were not identified. * S *

This species seems to be somewhat gregarious. In 1914, in one small clearing, five males were heard singing at the same time. In 1915, in the same clearing, three males were heard singing at once, and two nests were found. In almost every clearing of suitable size at least two pairs of birds were found, the nests being sometimes located rather close together. * * *

On the second day of our sojourn, June 19, we visited one of the typical nesting places of this warbler, a boggy cleared swale, with scattering, small second growth, and soon flushed a female from a nest containing six fresh, or practically fresh, eggs. This nest, typical of the majority of those found In both construction and situation, was placed In the side of a small tussock, bedded in moss and completely overhung by the dead grass of the previous year’s growth. The nest was composed entirely of fine, nearly white, dead grass stems. From the front rim protruded outward and downward, a wisp of dead grass tips, lying over the lower grasses in the tussock, and shingled over by the overhanging grass, establishing a continuity of the side of the tussock, thus cunningly adding to the perfect concealment. A tiny tree and one or two bush shoots grew from the tussock, close to the nest and this feature was typical of the greater number of the nests found.

They give the measurements of four nests; the outside diameter varied from 3 to 4 inches, the inside diameter from 1Y8 to 2 inches, the outside depth from 2 to 31,4, and the inside depth from l1/~ to 1Y2 inches. What nests I have seen, in collections, all appeared much flatter than the above measurements indicate, but they were probably flattened in transit. All that I have seen seemed to consist entirely of very light, straw-colored grass rather lightly arranged. Some observers mention moss in the composition of the nest, but the nests are evidently made in the moss and not of it.

Dr. Paul Harrington mentions in his contributed notes four nests that he found near Sudbury, Ontario: “The nests were all similarly situated in a clump or mound of sphagnum, well arched so that to obtain a full view of the nest it was necessary to part the sphagnum, in shaded areas on the borders of black spruce bogs. These, and others I have examined, have always been constructed entirely of fine straw-colored grasses, whereas in those of the Nashville warbler a few hairs or gold-threads were generally incorporated in the structure.”

Philipp and Bowdish (1919) record in a later paper the finding of a number of additional nests in New Brunswick, and say: “The experience of the past two years has demonstrated that while the boggy ground nesting, previously described, is the really typical and by far the most common form, not a few of these birds nest on higher and dryer ground. One such nest, found June 24, 1918, was well up on a steep hillside, in rather open woods, on fairly dry ground, utterly devoid of moss and grass cover. It was built among a thick growth of dwarf dogwood, and under a tiny, crooked stemmed maple sapling, very well concealed, and was rather more substantially built than the average nest of this species.”

The nesting history of the Tennessee warbler would not be complete without mentioning two authentic records made in 1901. J. Parker Norris, Jr. (1902), reported receipt of a set of four eggs, collected by Major Allan Brooks on June 15, 1901, at Carpenter Mountain, Cariboo, British Columbia. This is apparently the first authentic set of eggs ever taken, as those mentioned above by Professor Cooke were taken a few days later. In this far western locality, the birds “generally frequented the clumps of aspen trees and Norway pines, where the ground was covered with a thick growth of dry pine grass.” Major Brooks found several other nests in the same locality, and says in his notes: “The nests were always on the ground, sometimes at the foot of a small service berry bush or twig. They were all arched over by the dry pine grass of the preceding year, this year’s growth having just well commenced.” The Fort Smith nests, referred to by Professor Cooke, were recorded by Edward A. Preble (1908) as follows:

Nests containing eggs were found by Alfred E. Preble on June 20 and 27, the eggs, five In number, being fresh In each Instance. The first nest was embedded In the moss at the foot of a clump of dead willows near the edge of a dense spruce forest. It was rather slightly built of dead grass with a lining of the same material, and was protected from above by the overhanging bases of the willows, and by the strips of hark which had fallen from them, so that the nest could be seen only from the side. The second nest was more bulky, was composed outwardly of shreds of bark, coarse grass, and Equ~aetum stems, and was lined with fine grass. It was placed on the ground beneath a small fallen tree, in a clearing which bad been swept by fire a year or two previously.

XV. J. Brown, of Westmount, Quebec, tells me that he and L. ML Terrill in an hour found 16 nests of this warbler in a corner of a sphagnum bog, and, “there must have been about 100 pairs nesting in this ideal spot at the time.”

Eggs: The Tennessee warbler lays large sets of eggs, from four to seven, with sets of six common. Philipp and Bowdish (1919) state, “it appears that more full layings of six eggs are to be found than of five.”

The eggs are ovate to short ovate and have only a slight luster. The ground color is white or creamy white, and the markings, in the form of speckles and small spots, are in shades of “chestnut” and “auburn,” sometimes intermingled with “light vinaceous-drab.” On some the markings are well scattered over the entire surface while on others they are concentrated at the large end, often forming a loose wreath. Only occasionally do the spots assume the proportions of blotches. The measurements of 50 eggs average 16.1 by 12.4 millimeters; the eggs showing the four extremes measure 17.8 by 12.7, 16.8 by 13.1, 14.8 by 12.3, and 15.8 by 11.4 millimeters (Harris).

Young: Nothing seems to have been recorded on the period of incubation, which is performed by the female alone. Nor do we know anything about the care of the young or their development.

Plumages: Dr. Dwight (1900) says that the young Tennessee warbler in juvenal plumage, in which the sexes are alike, is similar to the young Nashville warbler in similar plumage but lacks the brownish cast and has a faint transocular stripe. He describes it as “above dull grayish olive-green, the rump brighter. Wings and tail clove-brown, the primaries whitish edged, the secondaries, tertiaries and wing coverts greenish edged with two yellowish white wing bands. Below grayish buff rapidly fading when older to a greenish gray; abdomen and crissum pale straw-yellow. Trace of ducky transocular streak.”

The incomplete postjuvenal molt, involving 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 the first winter plumage, in which the young male is “above, bright olive-green, gray tinged on the pileum. Below, olive-yellow darker on the flanks, the abdomen and crissum white. Superciliary line and orbital ring buff. Transocular streak dull black.” The young female “differs from the male in having the lower parts more washed with olive-green.” Young and old birds are now practically indistinguishable.

Dickey and van Rossem (1938) say that the prenuptial molt “begins in late February and is not finished before about the middle of March. The molt involves most of the anterior body plumage, but progresses so slowly that this species never has the ragged ‘pinfeathered’ appearance so often seen in Dendroica aestiva at the spring molt.” Dr. Dwight noticed the beginning of this molt as early as January 14. He says it “involves chiefly the head, chin and throat. The ashy gray cap is acquired, the chin, throat, and superciliary line become white, the throat is tinged with cream-buff and the transocular streak black. The yellow tints of the feathers retained below are lost by wear.” In the female, this molt is less extensive than in the male, and “the crown never becomes, even in later plumages, as gray as that of the male, but always has a brown or greenish tinge.”

Subsequent molts consist of a complete postnuptial in July and a partial prenuptial molt in late winter and early spring as in the young bird.

Food: Bowdish and Philipp (1916) sent four stomachs of birds collected in June to the U. S. Biological Survey for analysis. One of these was eml)ty. Of the other three, one contained 8 small caterpillars (Tortricidae), 35 percent; dipterous fragments, 23 percent; a small spider, 2 percent; and scalelike fragments (perhaps of some catkin), 40 percent. Another held a camponotid ant, 16 percent; at least ’18 small caterpillars (Tortricidae), 75 percent; a snail (Vitrea hammoides), 4 percent; and unidentified vegetable fragments, 5 percent. The other contained 3 lampyrids (near Podabrus) , 8 percent; a small coleopterous (I) larva, 3 percent; about 15 small caterpillars (as above), 25 percent; a neuropterous insect (apparently a caddis fly), 50 percent; 2 small spiders, 14 percent; and a trace of unidentified vegetable matter.

Several observers have complained that Tennessee warblers do considerable damage to grapes, and this is undoubtedly true. W. L. McAtee (1904), while investigating the damage done by this and the Cape May warbler, found that: in the arbor under observation, which was a small one, scarcely a grape and not a cluster was missed. The damage, however, was inconsiderable as the birds did not commence to use their appropriated share of the crop until the owner had taken all he desired. * 0 * Both species were constantly busy catch. ing insects on the vines, and on a walnut and some appletrees near by. Frequenuy, however, they dashed Into the vines and thrust their bills quickly into a grape. Sometimes they withdrew them quickly; again they poked around in the interior of the grape a little, and always after these attacks, they lifted their heads as in drinking. This action suggested a reason for piercing the grapes, that I am satisfied Is the true one, that is, the obtaining of Uquld refreshment.

A supply of available drinking water for the birds, might help to protect the grapes. And, as the warblers feed on insects that seriously damage the grapevines, the good work they do may compensate for the grapes that they damage. The stomach of one Tennessee warbler examined by Mr. McAtee contained a Typhiocyba come*, an especial pest of the grape, a destructive jassid or leafhopper, 6 caterpillars which were doing all in their power to eat up the leaves remaining on the vines, 2 spiders, a bug (Corizus), a weevil, and one parasitic bymenopteron (the only insect that was not harmful).

S. A. Forbes (1883) found that a stomach taken from an orchard infested by canker-worms contained about 80 percent of these destructive larvae and about 20 per cent beetles. Professor Aughey (1878) observed these warblers catching young locusts in Nebraska. Clarence F. Smith adds, in some notes sent to me, that “in the fall, during migration time, Tennessee warblers often glean their food from dense patches of such weeds as sunflower, goldenrod, and ragweed,” and that “sumac, poison ivy, and other berries are sometimes eaten in small quantity.”

F. H. King (1883) has considerable to say about the damage done to Delaware and Catawba grapes in Wisconsin; as soon as they are wounded, they are attacked by ants, bees, and flies and soon destroyed. But he thinks the service rendered more than compensates for the harm done. He refers to the feeding habits of the Tennessee warbler as follows:

It Is very dexterous In its movements, and obtains the greater part of Its food upon and among the terminal foliage of trees. Titmouse-like, it often swings pendant from a leaf while it secures an insect which it has discovered. Small Insects of various kinds, not especially attractive to larger birds, are destroyed by this species In large numbers; and its slender, acute bill serves It much better in picking up these forms than a heavier, more clumsy one could. * * * Of thirty-three specimens examined, two had eaten two very small hymenoptera (probably parasitic) ; seven, thirteen caterpillars; three, fifteen diptera; six, thirteen beetles; three, forty-two plant-lice, among which were two specimens of the corn plant-louse Ap7~s maidia (7); three, thirty-five small heteroptera, .09 of an Inch long; and one, eleven Insect eggs.

Alexander F. Skutch has sent me the following interesting notes on the feeding habits of the Tennessee warbler in Central America: “I was surprised to find last month [March] that these warbiers were visiting my feeding shelf on the guava tree in the yard. About the only food I ever serve to the birds on this table is bananas and occasionally plantains; and my chief guests are tanagers of about half a dozen brilliant kinds, a few finches, honeycreepers, and wintering Baltimore orioles. But the Tennessee warbiers soon formed the habit of visiting the table and sharing the food with the bigger resident birds.

Some seemed to linger in the vicinity much of the day, making frequent visits to the board and each time eating liberal portions of banana or the somewhat harder ripe plantain. They were intolerant of each other, and one individual would not let a second alight on the board until it had finished its own meal, although there was plenty of room and plenty of food for all. I have noticed also that the Tennessee warblers chase each other as they forage among the trees in wintering flocks. I cannot recall ever having seen any other wood warbler eat banana.

“Last November 14 a Tennessee warbler behaved most surprisingly. The grass in the yard had grown very long, and I had it cut with a machette. Late in the afternoon, after the usual rain, a lone Tennessee warbler flew down on the fallen grass and began to hop over it, catching small insects.

“It also entered the uncut grass, about a foot high, and disappeared momentarily amidst it. Twice driven up by passing people, each time it promptly returned to the grass. Its third visit to the cut grass was longest. While I stood quietly watching, it hopped deliberately about, much in the manner of a house wren, and gathered an abundant harvest from the fallen herbage. Once it found a caterpillar about an inch long, which it carefully bruised in its mandibles before swallowing it. The warbler was amazingly bold, and hopped over the grass within a yard of my feet, and allowed me to follow closely as it moved away. Early the following morning, and again at the close of the day, the warbler foraged over the lawn in the same fashion. In the evening, it continued to creep slowly over the mown grass and after all other birds had disappeared into their roosts, and the light was becoming too dim to see it clearly.”

Behavior: Much of the behavior of the Tennessee warbler has been mentioned above, and there is little more to be said. It is a very close sitter on its nest, when incubating, and has been caught there by throwing a hat or a net over it; but, when flushed, it is rather shy about returning to it, usually making its demonstrations of protest by flitting about at a safe distance and nervously uttering a sharp chip.

The Prebles (1908) witnessed a rather remarkable flight behavior at Fort Resolution, Mackenzie:

During the forenoon of June 25, an extremely windy day, we observed a remarkable movement of these warbiers. They came from the northward, flying oier the point of land on which the fort is built in ioose flocks of from 10 to 20 individuals. After passing the point, they either struck out directly across the bay or skirted the shore, in either case having to face a strong southeast wind. Some paused a few moments among the low bushes on the point, but the slightest alarm started them off. The flight lasted over two hours, and, during this time, upward of 300 birds were seen from our cnmp. Two specimens, a male and a female, were collected. The ovaries of the female contained eggs only slightly developed.

Voice: Aretas A. Saunders contributes the following: “The song of the Tennessee warbler is a rapid series of short, loud, unmusical notes. It has been compared to the song of the chipping sparrow, but it varies more in pitch, time, and loudness, and is distinctly in two or three parts. To my ear it is much more like the chippering of a chimney swift.

“In 35 records of this song, the number of notes varies from 9 to 25, the average being 17. Only one song has a true trill in it, that is, notes ~o rapid that they cannot be counted. Each song is of either two or three parts, each part composed of a series of notes on the same pitch and in uniform rhythm. The parts differ from each other in pitch, time, or loudness. In a number of songs, one of the parts is a repetition of 2-note phrases. Loudness generally increases to the end of the song, but sometimes the reverse is true. Some songs rise in pitch to the end and others fall; my records are about evenly divided in this matter. A typical three part song would be something like

tit it it it it it it pita pita pita pita pita chit chit chit chit chit.

“Pitch varies from G”‘ to E””, or four and a half tones. Single songs vary from half a tone to three and a half tones, averaging one and a half. The length of songs varies from 14A to 31/s seconds. An individual bird may sing a dozen different variations of the song in a short time. On the other hand, I have heard three birds in one tree singing alternately, the songs of all three being exactly alike so far as my ear could determine.”

Francis H. Allen gives me his impression of the song as follows: “The song bears some resemblance to that of the Nashville warbler, but is easily distinguished. I have written it

wi-chip wi-chip wi-chip wi-chip, wi-chip wi-chip chip chip chip chip chip chip chip.

The higher notes in the middle sometimes appear to be monosyllables, and they are sometimes omitted. The series of chip* at the end are very emphatic, and the last one is perhaps accented somewhat. All the notes are staccato.”

Various other renderings of the song have appeared in print, but they all give the same impression of a variable, loud, striking song which, once learned, can be easily recognized. The bird is a very persistent singer rivaling the red-eyed vireo in this respect. Bowdish and Philipp (1916) write: “As a basis for estimating the frequency of song repetition, counts were kept on three singing birds for a period of 5 minutes each, with a result of 32, 36, and 22 songs, respectively, within the period. In one instance, a bird was observed to sing while on the wing, repeating the song twice in the course of a short flight.” Albert R. Brand (1938) found the pitch of the Tennessee warbler’s song to be well above the average, the approximate mean count being 6,600 vibrations per second, the highest note about 9,150 and the lowest 4,025; this compares with an approximate mean of 8,900 vibrations per second for the black-poll warbler, and about 4,000 for the average passerine song.

Field marks: .The Tennessee warbler has no prominent wing-bars and no very conspicuous field marks. It might be mistaken for one of the small vireos, but its bill is much more slender and acute. The male has a gray crown, a light line over the eye, and a dusky line through it; the upper parts are bright olive-green and the under parts grayish white. The female has a greener crown and more yellowish under parts. For more details, see the descriptions of plumages.

Fall: The fall migration starts early in August, but is quite prolonged, many birds lingering in the northern States until early in October and in the southern States all through that month. During some seasons and at certain places the Tennessee warbler is exceedingly abundant, sometimes far outnumbering any other species, but it is very variable in its abundance.

Mr. Trautman (1940) says that at Buckeye Lake, Ohio, “during some years not more than 20 individuals could be recorded in a day in the southward migration, nor more than a 100 in the season. In other years the bird rivaled the Myrtle Warbler in numbers, and as many as 1,000 individuals could be seen in a day and several thousands during a migration. * * * Throughout the southward migration the species did not confine itself to the upper sections of the taller trees as in spring, but ~vas found in almost equal numbers in smaller trees and brushy thickets, in bushes and saplings along fence rows, and in weedy fields.”

Professor Cooke (1904) says of the fall migration route: “The principal line of migration is from the Mississippi Valley across the Gulf of Mexico to Mexico and Central America. The eastern part of this route probably extends from the southern end of the Alleghenies across northwestern Florida to the coast of Yucatan and Honduras.” A. H. Howell (1932), however, gives several records for central and southern Florida., and says: “In autumn, Weston reports a large migration on October 26 and 27, 1925, when 31 birds were killed at the lighthouse near Pensacola on the two nights, and large numbers seen on the morning of October 26 in vacant lots in the city.”

Dickey and van IRossem (1938) say of the migration in El Salvador:

During the fall migration of 1925, Tennessee warbiers arrived in the vicinity of Divisadero on October 13. No advance guard, that is, individuals arriving ahead of the main flights, was observed in this case. On the above-mentioned date they were suddenly found to be present in numbers, and from then on were common In every lowland or foothill locality visited. In point of relative abundance this was by far the most common warbler (resident or migratory) throughout the coastal plain and in the foothills, but it was greatly outnumbered by Dendroica vtrens above 8,000 feet.

The manner of occurrence was usually as small flocks of six or eight or even twenty or more birds. These combined with several other species to make up larger flocks which worked ceaselessly through the crown foliage of low, semiopen woodland. However, many were found even in the tall, dense swamp forests along the coast and also in the oak woods on Mt. Cacaguatique.

Winter: Dr. A. F. Skutch has contributed the following account: “The Tennessee warbler winters in Central America in vast numbers. Coming later than many other members of the family, the first individuals appear in mid-September; but the species is not abundant or widely distributed until October. During the year I passed on the Sierra de Tecp~n in west-central Guatemala a single Tennessee warbler appeared in the garden of the house, at 8,500 feet, on November 7 and despite frosty nights lingered into December. On November 19, 1935, I saw one on the Volc~¶n Irazii in Costa Rica at 9,200 feet: the highest point at which I have a record of the species. At the other extreme I found a few of these adaptable birds among the low trees on the arid coast of El Salvador in February and among the royal palms at Puerto Lim6n, on the humid coast of Costa Rica, in March. But Tennessee warblers are most abundant as winter residents at intermediate altitudes, chiefly between 2,000 and 6,000 feet above sea-level. From 3,000 to 5,000 feet they often seem to be the most abundant of all birds during the period of their sojourn. They travel in straggling flocks and form the nucleus of many of the mixed companies of small, arboreal birds. At times ‘myriads’ is the only term that seems apt to describe their multitudes.

“I think ‘coffee warbler’ would be a name far more appropriate than Tennessee warbler for this plainly attired little bird; it was merely a matter of chance that Alexander Wilson happened to discover the species in Tennessee rather than at some other point on its long route from Canada to Central America; but the warblers themselves manifest a distinct partiality to the coffee plantations. The open groves formed by the shade trees, whose crowns rarely touch each other, yet are never far apart, seem to afford just the degree of woodland density that they prefer. It matters not whether these trees are Grevilleas from Australia with finely divided foliage, or Ingas with large, coarse, compound leaves, or remnants of the original forest: a mixture of many kinds of trees with many types of foliage: from Guatemala to Costa Rica the Tennessee warblers swarm in the coffee plantations during the months of the northern winter and are often the most numerous birds of any species among the shade trees. Possibly they may at certain times and places be as multitudinous in the high forest as in the plantations. Although I have never found them so, the negative evidence must not be allowed to weigh too heavily, for such small, inconspicuous birds, devoid of bold recognition marks, are not easy to recognize among the tops of trees over a hundred feet high.

“Tennessee warblers are fond of flowers, especially the clustered heads of small florets of the Compositae and Mimosaceae, and of the introduced Grevilica that sometimes shades the coffee plantations. They probe the crowded flower clusters, perhaps seeking small insects lurking there rather than nectar. The white, clustered stamens of the Inga: the most generally used shade tree of the coffee plantations: are especially attractive to them. Local movements within their winter range appear to be controlled by the seasonal abundance of flowers. So, in the valley of the Rio Buena Vista in southern Costa Rica, at an altitude of about 3,000 feet, I found Tennessee warblers very abundant during December and January. Here they flocked not only in the forest and among the shade trees of the little coffee groves, but also in great numbers through the second-growth thickets that filled so much of the valley, where at this season there was a profusion of bushy composites with yellow or white flowerheads, and of acacia-like shrubs (Ca iliandra portoricensis) with long, clustered, white stamens. But during February, the third dry month, t.he thickets became parched and flowered far more sparingly. Now the Tennessee warblers rapidly declined in numbers, and before the end of the month disappeared from the valley. During the following year, which in its early quarter was far wetter, a number remained through March, and a few well into April.

“Tennessee warblers pluck the tiny, white protein corpuscles from the brown, velvety bases of the long petioles of the great-leafed Cecropia trees, taking advantage of these dainty and apparently nutritious tid-bits when the usual Azteca ants fail to colonize the hollow stems; for only on trees free of ants does this ant-food accumulate in abundance.

“While the Tennessee warbler departs during February from some districts where it is common in midwinter, it remains until April in regions where. the dry season is not severe. After the middle of April it is only rarely seen in Central America; and there appears to be no record of its occurrence in May.”

DISTRIBUTION
Range: Canada to northern South America.

Breeding range: The Tennessee warbler breeds north to southwestern Yukon (Burwash Landing and the Dezadiash River); southern Mackenzie (Mackenzie River below Fort Wrigley, lower Grandin River, and Pike’s Portage); northeastern Manitoba (Churchill and York Factory); central Quebec (Fort George, Lake Mistassini, and Mingan); and possibly southern Labrador (Hawkes Bay). East to southeastern Labrador (Hawkes Bay); central Newfoundland (Lamond and Gaff Topsail). South to central Newfoundland (Gaff Topsail); Nova Scotia (Wolfville); southern New Brunswick (Grand Manan); northern and central western Maine (Mount Katahdin, Livermore, and Lake Umbagog); north-central New Hampshire (Mount Washington) ; south-central Vermont (Rutland); possibly northwestern Massachusetts (Hancock); southern New York (Slide Mountain) ; southern Ontario (Ottawa, North Bay, and Biscotasing; probably occasionally farther south) ; west-central Michigan (Duck Lane) ; probably northern Wisconsin (Plum Lake); northern Minnesota (Tower, Cass Lake, and Warren) ; southwestern Manitoba (Margaret and Aweme); central Saskatchewan (Emma Lake; has been found in the breeding season at Indian Head, Old Wives Creek, and Maple Creek) ; southern Alberta (Flagstaff, Red Deer, and Banff); and south-central British Columbia (150 Mile House and Kimquit). West to western British Columbia (Kimquit, Hazelton, Telegraph Creek, and Atlin); and southwestern Yukon (Dezadiash River and Burwash Landing). Winter range: In winter the Tennessee warbler is found north to central Guatemala (Volc6n de Santa Maria, Cob6n, and Gualf~n). East to eastern Guatemala (Gual~tn); northeastern El Salvador (Mount Cacaguatique); eastern Nicaragua (Rio Escondido); eastern Costa Rica (Puerto Lim6n); eastern PanamA (Barro Colorado and Perm~); northern Colombia (Santa Marta region); and northern Venezuela (Caracas). South to northern Venezuela (Caracas and M6rida); and northwestern Colombia (Concordia). West to western Colombia (Concordia and Antioquia) ; PanamA (Paracat~) ; Costa Rica (El General and Liberia) ; El Salvador (Puerto de Triunfo); and Guatemala (TecpAn and Voldin de Santa Maria). It has also been found to the first of January (possibly delayed migration) at Knoxville (1936) and at Nashville (1935), Tenn.; and one wintered (1934: 35) in Cameron County, Tex. Migration: Late dates of departure from the winter home are: Colombia: Miraflores, April 19. Costa Rica: San Isidro del General, April 30. El Salvador: San Salvador, April 25. Guatemala: Livingston, April 8. Chiapas: Tixtla Guti~rrez, May 8. Tamaulipas: G6mez Farias, April 27. Early dates of spring arrival are: Cuba: Habana, April 8. Florida: Sandy Key, April 13. Georgia: Athens, April 13. District of Columbia: Washington, May 2. West Virginia: French Creek, April 20. Pennsylvania: McKeesport, April 27. New York: Corning, May 3. Massachusetts: Northampton, May 8. Maine: Wateryule, May 11. New Brunswick: Petitcodiac, May 19. Quebec: Quebec, May 19. Louisiana: Avery Island, April 6. Arkansas: Winslow, April 8. Tennessee: Memphis, April 9. Kentucky: Bowling Green, April 19. Indiana: Bloomington, April 12. Ohio: Columbus, April 25. Michigan: Ann Arbor, April 21. Ontario: Ottawa, May 12. Missouri: Columbia, April 22. lowa: Sigourney, April 25. Wisconsin: St. Croix Falls, April 25. Minnesota: Clarissa, April 30. Kansas: Winfield, April 19. Nebraska: Red Cloud, April 18. South Dakota: Vermillion, May 1. North Dakota: Fargo, May 1. Manitoba: Margaret, May 3. Colorado: Estes Park, May 14. Wyoming: Torrington, May 12. Montana: Great Falls, May 9. Alberta: Belvedere, May 1. British Columbia: Carpenter Mountain, Cariboo, May 15; Atlin, May 26.

Late dates of spring departure of transients are: Cuba: Habana, May 5. Florida: Fort Myers, May 15. Alabama: Melville, May 3. Georgia: Athens, May 7. North Carolina: Chapel Hill, May 3. Virginia: Falls Church, June 3. District of Columbia: Washington, June 3. Pennsylvania: Warren, May 30. New York: Rochester, June 6. Massachusetts: Beverly, June 3. Vermont: Wells River, June 5. Louisiana: Shreveport, May 15. Mississippi: Oxford, May 15. Arkansas-Delight, May 20. Tennessee: Nashville, May 21. Illinois: Lake Forest, June 3. Ohio: Toledo, June 5. Michigan: Houghton, June 7. Ontario: Toronto, June 7. Missouri: Columbia, May 31. Iowa: Sioux City, June 6. Wisconsin: Racine, June 4. Minnesota: St. Paul, June 1. Kansas-Lawrence, May 24. Nebraska: Omaha, May 28. South Dakota: Faulkton, June 5.

Late dates of fall departure are: British Columbia: Atlin, July 26; 16-mile Lake, Cariboo, August 28. Alberta: Glenevis, September 13. Montana: Fortine, September 11. Wyoming: Laramie, October 5. Saskatchewan: Wiseton, September 29. Manitoba: Aweme, October 3. North Dakota: Fargo, October 8. South Dakota: Arlington, October 8. Nebraska: Lincoln, October 14. Kansas: Lawrence, October 22. Oklahoma: Fort Sill, October 19. Minnesota: Hutchinson, October 11. Wisconsin: Madison, October 19. Iowa: National, October 17. Missouri: St. Louis, October 19. Michigan: Ann Arbor, October 30. Ontario: Port Dover, October 10. Ohio-Columbus, October 31. Illinois: Evanston, October 28. Tennessee-Nashville, October 23. Arkansas: Jonesboro, October 19. Louisiana: New Orleans, November 8. Mississippi: Gulfport, November 12. Quebec: Montreal, September 28. Vermont: Wells River, September 29. Massachusetts: I-Iarvard, October 1. New York: Rhinebeck, October 14. Pennsylvania: Beaver, October 26. District of Columbia: Washington, October 22. North Carolina: Mount Mitchell, October 1. Georgia: Dalton, October 30, Alabama: Birmingham, October 25. Florida: Pensacola, November 4. Cuba: Habana, November 10.

Early dates of fall arrival are: Wyoming: Laramie, August 28. South Dakota: Lennox, August 30. Kansas: Topeka, August 29. Wisconsin: Delavan, August 19. Illinois: Glen Ellyn, August 17. Missouri: Monteer, August 20. Ohio: Toledo, August 19. Tennessee: Knoxville, September 15. Arkansas: Hot Springs, September 19. Louisiana: Monroe, September 14. Mississippi: Gulfport, September 5. Vermont: Woodstock, August 22. Massachusetts: Lexington, August 11. Pennsylvania: Jeffersonville, August 27. District of Columbia: Washington, August 31. Virginia: Salem, August 23. North Carolina: Blowing Rock, September 1. Georgia: Atlanta, September 9. Alabama: Leighton, September 17. Florida: Fort Myers, September 20. Cuba: Habana, October 13. Guatemala: Huehuetenango, September 11. Nicaragua: Rio Escondido, October 24. Costa Rica: San Jos~, September 17. Panam~: New Culebra, October 24. Colombia: Santa Marta Region, October 14.

Casual records: In 1898 an adult male of this species was found dead at Narssag, Greenland. In Bermuda one was seen on March 2, 1914, and it remained about six weeks.

Egg dates: Alberta: 6 records, June 1 to 16.

New Brunswick: 82 records, June 10 to July 10; 46 records, June 17 to 26, indicating the height of the season.

Quebec: 30 records, June 8 to 29; 21 records, June 17 to 27.