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."
_Behavior._--The eastern Nashville warbler is an active, sprightly,
restless member of an active family, ranging in its foraging mainly in
the lower story of the open woodlands and more often in the low trees
and shrubbery around the borders of the forest. When thus engaged it is
not particularly shy and often seems quite unconscious of the presence
of an observer. On migrations it seems to be sociably inclined and may
be seen associated with the mixed flocks of warblers that are drifting
through the tree tops. At these seasons it often visits our orchards and
the shrubbery in our gardens, giving us a glimpse of green and gold
among the blossoms and opening leaves.
J. W. Preston (1891) describes an interesting manner of foraging:
"One will fly to the foot of a fir tree or other conifer and begin an
upward search, hopping energetically from branch to branch until the
very highest point is reached, when the bird drops lightly down to the
foot of another tree, much as does the Brown Creeper. When an insect is
discovered the bird secures it by a sudden bound, and, should the object
be not easily dislodged, _Helminthophila_ sustains himself on flapping
wings until his purpose is accomplished, which often requires several
moments."
_Voice._--Gerald Thayer gave Dr. Chapman (1907) a very good description
of the songs and calls as follows:
The Nashville has at least two main perch-songs, and a flight-song, all
subject to a good deal of variation. It belongs decidedly among the
full-voiced Warblers. * * * Its commoner perch-song consists of a string
of six or eight or more, lively, rapid notes, suddenly congested into a
pleasant, rolling twitter, lower in key than the first part of the song,
and about half as long. In the other perch-song, the notes of what
correspond to the rolling twitter are separate and richer, and the
second part of the song is longer and more noticeable than the first,
whose notes are few and slurred, while the whole is more languidly
delivered.
The differences are hard to describe intelligibly; but in reality they
are pronounced and constant. The flight-song, a fairly common
performance in late summer, is sung from the height of five to forty
feet above the (usually low) tree-tops. It is like the commoner
perch-songs, but more hurried, and slightly elaborated, often with a few
_chippings_ added, at both ends. Among the Nashville's calls a very
small, dry _chip_, and a more metallic, louder _chip_, somewhat
Water-Thrush-like, are noteworthy. It also _chippers_ like a young
Warbler or a Black-throated Green.
Miss Stanwood (1910a) writes:
One common song sounds like _'tsin, 'tsin, 'tsee_, another _sweeten,
sweeten, 'tsee_, a third, _sillup, sillup, sillup, 'tsee-e-e-e-e-e_. At
other times the bird sings but part of the song as _sweeten, sweet_; or
_sweeten, 'tsee_; or _sweeta, sweeta, 'tsee_; or recombines them
differently as _sweeten, sweeten, sweeten, 'tsee-e-e-e-e-e_. * * *
The song is loud, constant, and heard all over the locality, coming
principally from the gray birches, but also from the maples, poplars,
and evergreens. The bird sings from the tree-tops, but likewise from the
middle branches, and I have seen it singing on the ground and just a few
inches above it. My last record of its song in 1908 was made the 17th
day of July, the first, May the 14th. Between these dates it sang
well-nigh incessantly.
Knight (1908) says that, while the female is building the nest,
"the male bird perches in a nearby sapling and sings leisurely
'_pea-cie-pea-cie-hit-i-hit-i-hit_.'" Wilson (1832) thought that the
"notes very much resembled the breaking of small dry twigs, or the
striking of small pebbles of different sizes smartly against each other
for six or seven times, and loud enough to be heard at the distance of
thirty or forty yards." Rev. J. H. Langille (1884) writes: "The song of
the Nashville Warbler is a composition, the first half of which is as
nearly as possible like the thin but penetrating notes of the
Black-and-white Creeping Warbler, while the last half is like the
twitter of the Chipping Sparrow." He writes it in syllables as
"_ke-tsee-ke-tsee-ke-tsee-chipe-ee-chip-ee-chip-ee-chip_."
The song has been said to resemble that of the chestnut-sided warbler,
but the two are really quite distinct; the song of the latter does not
end in a trill or in chipperings. It does, however, more closely
resemble the song of the Tennessee warbler. Dr. Roberts (1936) heard the
two singing at the same time and noted this difference: "The Nashville's
song is an utterance of rather greater volume than that of the Tennessee
and differs, also, in the fact that it has a short, rapidly weakening
trill or slide, following a rather long and deliberate prelude of four
or five notes; while the Tennessee has a brief prelude with a long
finishing trill, increasing in loudness and intensity to an abrupt
ending."
Aretas A. Saunders contributes the following study of the song: "The
territory song of the Nashville warbler is in two parts, the first a
series of 2-note phrases, and the second a series of rapid notes,
commonly lower in pitch and just twice as fast as the notes of the first
part; _pa tipa tipa tipa tipa tititititititit_. In 26 of my 29 records
the second part of the song is lower than the first. In the other three
it is higher. "The pitch of songs varies from G´´´ to F sharp´´´´, or
five and a half tones. Single songs rarely vary more than one and a
half or two tones. They are from 1-2/5 to 2 seconds in length. The
quality is rather musical, and some individuals have almost as sweet a
tone as the yellow warbler. In my experience field students often
confuse the songs of these two species.
"The nesting song may be heard commonly on the breeding grounds. I have
several records from the Adirondacks. This song is in three or four
parts, each part of three or four notes, and a little lower in pitch
than the preceeding part. Two-note phrases are not commonly heard in the
nesting song."
Francis H. Allen's rendering of the song is not very different from the
first one of Mr. Saunders', though he noted some variation, and mentions
in his notes an aberrant song, which "doubled the common song, which in
this case had a first part consisting of only a single phrase, thus;
_chip-ee-_(trill) _chip-ee-_(trill)."
_Field marks._--The gray head, white eye ring, olive-green back, bright
yellow under parts, and the absence of wing bars, with no white in the
tail, are the distinguishing marks of the eastern Nashville warbler. The
Connecticut warbler has a white eye ring but it has a gray throat,
whereas the Nashville is bright yellow from chin to abdomen. The
chestnut crown patch is not very conspicuous in the male and is less so,
or entirely lacking, in the female; the female is duller yellow below
and browner above than the male.
_Enemies._--Like other ground-nesting birds, this warbler has the usual
four-footed enemies to contend with, but its nest is quite well hidden.
Perhaps its worst bird enemy is the cowbird, although Friedmann (1934)
listed it as an uncommon victim of this parasite and had only six
records of it, the nests containing from one to two eggs of the cowbird.
_Fall._--As soon as the molting season is over and the young birds
are freshly clad in their winter dress the migration begins in
Massachusetts. This takes place in August, and the last stragglers may
be seen passing through in early October.
In Ohio, according to Mr. Trautman (1940), the first migrants are seen
about the first of September, the peak of the migration coming during
the latter half of that month when from 10 to 100 could be found in a
day, and after the 10th of October only an occasional bird remains. He
writes: "As with many other transient warblers the southward migration
of the Nashville Warbler covered a greater period of time than did the
spring movement, which usually lasted less than 30 days, whereas the
fall movement generally extended more than 45 days. * * * In spring the
species frequented the upper half of large trees and was more numerous
in tall trees of woodlands than it was in smaller groups or rows of tall
trees. In fall the species tended to inhabit the middle section of large
trees, and it also resorted to the taller bushes and saplings,
especially the larger hawthorn trees."
The fall migration route is apparently a reversal of the spring route
southwestward into Mexico and Central America where it spends the
winter.
_Winter._--The Nashville warbler is evidently very common in winter in
certain parts of Mexico, for Dr. C. William Beebe (1905) says: "At
times there were twenty and thirty in sight at once near our camp in
the Colima lowlands." These may have been the western race.
DISTRIBUTION
_Range._--Southern Canada to Guatemala.