during the summer months, though in rather limited numbers, in the
higher pine regions from 8500 feet upwards. On one occasion, April 5,
1903, I secured a male _nigrifrons_ from a flock of _auduboni_ feeding
in some live-oaks near the mouth of one of the canyons at an altitude of
about 4500 feet, but this is the only time that I have seen it below the
altitude given above; and it is also exceptional in the early date of
its arrival. No more were seen until the second week in May, which seems
nearer the usual time of arrival, for in 1902, the first was seen on May
9th. * * * Several specimens were taken intermediate in their
characteristics between _auduboni_ and _nigrifrons_; some, of the size
of the latter, though in color but little darker than _auduboni_, while
some show every gradation of color between the two extremes.
The black-fronted warbler averages somewhat larger than the Audubon's.
_Nesting._--Before this warbler was known to be the breeding form in
Arizona, O. W. Howard (1899) reported on two nests found in the Huachuca
Mountains in 1898, and said that he had found "several nests" of
Audubon's warblers in 1897 and 1898, all in these mountains. These were
all, doubtless, nests of the black-fronted warbler. One of these was in
a red fir tree about 15 feet up, and the other "was placed in the lower
branches of a sugar-pine about fifty feet from the ground, and twelve
feet out from the trunk of the tree. * * * The nests are very loosely
constructed, being composed almost entirely of loose straws with a few
feathers and hair for a lining." One of Howard's nests of this warbler,
with four eggs, is in the Thayer collection in Cambridge. It was found
in the same mountains, at an elevation of about 9,000 feet, saddled on
the limb of a red spruce tree 35 feet above ground and well concealed in
the foliage. It is rather a bulky nest made of shredded weed stems, fine
strips of inner bark, fine rootlets and various other plant fibers,
mixed with feathers of the Arizona jay, three long wing feathers of
small birds and two small owl feathers; it is lined with fine fibers,
horse and cattle hair, and jay feathers. Externally it measures about
3-1/2 inches in diameter and 2-1/2 in height; the inside diameter is
about 2 inches and the cup is about 1-3/4 inches deep.
James Rooney has sent me the data for a set of four eggs of the
black-fronted warbler, taken by Clyde L. Field in the Santa Catalina
Mountains in Arizona, June 2, 1938. The nest, placed 15 feet above
ground at the end of a pine limb, was made of twigs and was lined with
deer hair and a few feathers. A nest with four eggs, in the collection
of Charles E. Doe, in Florida, was taken by the same collector in the
same mountains on June 8, 1937; it was in a crotch of an aspen, 30 feet
up.
_Eggs._--The measurements of 16 eggs average 18.5 by 13.6 millimeters;
the eggs showing the four extremes measure =19.8= by 14.0, 19.5 by
=14.4=, =17.3= by 13.9, and 17.6 by =12.4= millimeters (Harris).
DENDROICA NIGRESCENS (Townsend)
BLACK-THROATED GRAY WARBLER
PLATE 35
HABITS
The black-throated gray warbler is neatly dressed in gray-black and
white, with only a tiny spot of bright yellow in front of the eye. Its
breeding range extends from southern British Columbia, Nevada, northern
Utah, and northwestern Colorado southward to northern Lower California,
southern Arizona, and southern New Mexico. It spends the winter in
Mexico.
As a summer resident it is common and sometimes abundant in western
Washington, even at lower elevations where, Samuel F. Rathbun tells me,
it "prefers a locality somewhat open, with a second growth of young
conifers; this may occur in the rather heavy forest, if such condition
exists there, or along the edge of the timber; the species is partial to
this character of growth."
In southern Oregon, according to C. W. Bowles (1902), it seems to
combine the habitat requirements of the eastern black-throated green and
the prairie warbler. Like the former, it seeks tall trees, preferably
conifers, well scattered and interspersed with bushes, since it nests in
both. Like the prairie warbler, it chooses high dry places with dry
ground underneath for its nest.
Farther south, the black-throated gray warbler seems to prefer growths
of hardwood and underbrush for its summer haunts--oaks, scrub oak,
pinyon, juniper, manzanita, and the like. Dr. Walter K. Fisher wrote to
Dr. Chapman (1907) that, in California, "it lives in chaparral such as
deer brush, wild lilac of various species, scrub oak, and sometimes,
particularly in the humid coast districts, among evergreens. It is fond
of the neighborhood of clearings where it works constantly and carefully
among low growth." Dr. Grinnell (1908) says that in the San Bernardino
Mountains, "this warbler appeared to be be confined exclusively to the
golden oak belt during the breeding season." Referring to the Great
Basin region, Dr. Linsdale (1938) writes: "The black-throated gray
warbler was one of the few species adapted to occupy the piñon belt on
the Toyabe Mountains. Not only did this bird tolerate conditions on dry
slopes, but it was practically limited to them. The pairs were scattered
far apart, but because this type of habitat takes up so much of the
total area, this warbler must rank high among all the summer resident
birds on the basis of numbers."
This warbler is a common breeding bird in the mountains of southern
Arizona. In the brushy foothills and canyons of the Huachucas, we found
it between 4,000 and 7,000 feet in altitude, in the oak belt about
halfway up the canyons, principally among the scrub oaks and manzanita
bushes. In New Mexico, according to Mrs. Bailey (1928), it is found in
summer at slightly higher levels, 5,500 to 8,000 feet, in the oak and
pinyon pine country.
_Nesting._--In Washington, the black-throated gray warbler seems to nest
in fir trees exclusively, at heights ranging from 7 or 8 feet up to 50
feet above the ground. Rathbun has sent me the data for seven nests, all
in firs, at heights ranging from 7-1/2 to 35 feet; they were all on
horizontal branches and from 4 to 10 feet out from the trunk. He
describes in his notes a typical nesting site as follows: "From a
distance I saw a fir tree the character of which, from my experience,
was favored by this warbler as a nesting place. It was of considerable
size, one of a number scattered along the edge of the forest, and had
considerable undergrowth beneath. After a very careful examination I
located the nest near the extremity of one of the large lower limbs, at
a distance from the trunk of 9 feet and at a height above the ground of
23 feet. The nest was placed at the side of the limb and was securely
attached at a point where grew several small twig-like branches." He
says that this bird is very regular in its nesting date, the average
date for fresh eggs is between June 3 and 8, and that the nest is always
a neat one. He describes a typical nest as follows: "Plant fibers, dry
grasses and a few very small weed-stalks were all neatly woven together
to form the walls of the nest. The lining was a few feathers--two being
those of the ruffed grouse, with others from sparrows, the quill of each
being worked into the walls of the nest; next to this lining were soft
and very fine plant fibers, with a few horsehairs."
C. W. Bowles (1902) mentions a nest in southern Oregon that "was six
feet up in a manzanita bush in a patch of bushes of the same variety
about three acres in extent." But he adds that--
the nests were from three feet and three inches to twenty-five feet from
the ground, oaks seeming the favorite in southern Oregon and fir near
Tacoma. The usual situation is in a small clump of leaves that is just
large enough to almost completely conceal the nest, and yet so very
small that a crow or jay would never think of anything being concealed
in them. * * * The nests externally are about 3 × 2-3/4 inches and
internally 1-3/4 × 1-3/4 inches in diameter and depth. They are composed
externally of grass and weed-stalks, that must be several seasons old,
(being bleached and very soft) moss and feathers; and lined with
feathers (one had evidently been lined from a dead Stellar jay), horse,
cow and rabbit hair or fur, and sometimes the very fine stems of the
flowers of some kind of moss. The male has never been seen to assist
either at nest-building or incubation.
In the Yosemite region, where Grinnell and Storer (1924) found the
black-throated gray warbler in fair numbers among the golden oaks on the
north walls of the Valley, they found a nest "placed 5 feet 6 inches
above ground in a mountain lilac (_Ceanothus integerrimus_) bush against
a main stem."
From southern California, James B. Dixon writes to me: "This bird breeds
sparingly from 2,500 feet to the tops of our mountain ranges in San
Diego, Riverside and San Bernardino Counties. During my observations
since 1898, I have seen but five nests. One was in a live oak tree, two
in manzanita bushes and two in golden oak saplings." A nest in Riverside
County, at 5,500 feet elevation, was in "a scrub growth area which was
well wooded with sapling golden oak and manzanita, buck thorn, and other
sparsely growing bushes." The nest was "located 12 feet from the ground
in a deep, vertical crotch of a golden oak sapling, and could be seen
from only one angle, much like the nest of a gnatcatcher or wood pewee."
Another nest was found "in the dense growth of a young manzanita bush.
* * * The locations of the two nests were extremely different, one was
carefully concealed in a comparatively bare oak sapling, and the other
in the dense foliage of a rank-growing young manzanita bush."
In the Huachuca Mountains of Arizona, I found but one nest of the
black-throated gray warbler. It was 5 feet up in the main crotch of a
small oak growing on a steep slope on the side of a branch of Ramsey
Canyon; the slope was sparsely covered with scrub oaks and other bushes,
with a scattering of tall pines; the nest was so well concealed that I
could not get a clear photograph of it. Howard (1899) found three nests
in these mountains in upright forks of oak saplings, and says: "I found
other nests, some placed in large white oaks and some in sycamores and
have known the birds to build high up in pines." One of his nests from
these mountains, in the Thayer collection, was found only 18 inches up
in a young fir tree in a thicket; lying against the main stem, it was
supported, surrounded, and well concealed by live twigs. Four other
nests in this collection, were all taken in the Huachuca and Chiricahua
mountains from oaks at heights ranging from 6 to 16 feet above ground.
All much alike, their decidedly gray appearance makes them less visible
among the gray branches. They are made of light gray, old, shredded
stems of dead weeds and grasses, very fine gray plant fibers and a few
dead leaves, bits of string, and thread, all firmly bound with spider's
web and decorated with numerous bits of spider cocoons. They are lined
with fine brown and white hairs and small, soft feathers.
In New Mexico, Jensen (1923) reports two nests in piñon pines; one was 3
feet and the other 5 feet above ground.
_Eggs._--From 3 to 5 eggs, usually 4, constitute a full set for the
black-throated gray warbler. These are ovate to short ovate and are only
slightly glossy. The ground color is white or creamy white and is
speckled, spotted, and sometimes blotched with "chestnut," "auburn,"
"bay," or "russet," occasionally with "mummy brown," with underlying
spots of "light brownish drab," or "light vinaceous drab." The spots are
usually concentrated at the large end, forming a loose wreath, with the
drab markings frequently in the majority. Some eggs are only lightly
speckled, while others are boldly marked. The measurements of 50 eggs
average 16.5 by 12.5 millimeters; the eggs showing the four extremes
measure =18.2= by 12.3, 18.1 by =13.1=, =14.6= by 12.9, and 16.2 by
=11.6= millimeters (Harris).
_Young._--The period of incubation does not seem to have been recorded
for this warbler. It is probably performed by the female entirely, but
both parents share in the feeding of the young. Information on this
subject is scanty.
_Plumages._--The young black-throated gray warbler in juvenal plumage
shows the characters of the species more than do the young of other wood
warblers; the black and white areas about the head and throat are
strongly indicated in a duller pattern and there are two broad white
bars tipping the median and greater wing coverts (see pl. 35); these
markings are more subdued in the female than in the male, thus making a
slight sexual difference. The back is brownish gray and the underparts
grayish white, faintly streaked with black.
I have not been able to trace the postjuvenal molt, but it is perhaps
less extensive than in most other warblers. In first winter plumage the
young male is much like the adult male at that season, but it is more
strongly washed with brown above and with yellowish beneath, the chin is
white, the black throat is mottled with white, and the streaking above
and below is duller and more obscured. The young female differs from the
adult female in about the same way.
Apparently, the nuptial plumage is produced mainly by wear, or by a
limited prenuptial molt. The postnuptial molt is evidently complete in
late summer.
The adult winter plumages of both sexes differ but little from the
spring plumages; in the male, the feathers of the upper parts and cheeks
are margined with brownish gray and the throat with white, the sides are
washed with brown and the black streaks are obscured; in the female, the
plumage is tinged with brownish in the same way and the black streaks
are obscured.
_Food._--No extensive study of the food of the black-throated gray
warbler seems to have been made. It is evidently mainly, if not wholly,
insectivorous, for several observers have mentioned its zeal in foraging
among the foliage of trees and bushes for insects, with a special
fondness shown for oak worms and other green caterpillars. Bowles (1902)
says that "it seems to prefer oak trees in the spring because of the
small green caterpillars that are very numerous on them and which are
devoured on all occasions. One female must have eaten nearly half its
weight of them (from three-fourths to one and one-half inches long)
while its nest was being taken." Mrs. Wheelock (1904) writes in the same
vein: "In the spring these oaks are particularly infested with the green
caterpillars, and the Warblers never seem to tire of devouring the
pests. They lean way over to peer under every leaf, or reach up to the
twigs overhead, never missing one. Twenty of these worms is an average
meal for a Black-throated Gray Warbler, and the total for a day must
reach into the hundreds."
_Behavior._--The black-throated gray warbler is not one of the most
active wood warblers except when it is busy feeding; even then it goes
about it in a quiet, business-like manner, without much concern over the
presence of humans. At other times, it is rather shy and retiring,
difficult to follow, as it slips away silently in the thick underbrush,
where it spends so much of its time. Its nest is difficult to find, for
it is not only well concealed, but the bird is careful not to betray it;
our usual method of following a bird to its nest was not very
successful, as it was soon lost to sight while we were watching it.
Mr. Bowles (1902) writes of its behavior that an incubating female
"passed the time eating caterpillars while the nest was being examined.
She did not go over five feet from it this time, till I left when she
followed for about twenty feet, and kept almost within reach, watching
me very closely. * * * Black-throated gray warblers do not object to
human association at all; one nest was fifteen feet up on an oak branch,
directly over a trail that was used at least six times a day by people
going for mail, and generally much oftener."
William L. Finley (1904a) describes quite different behavior at a nest
containing young: "The moment the mother returned and found me at the
nest she was scared almost out of her senses. She fell from the top of
the tree in a fluttering fit. She caught quivering on the limb a foot
from my hand. But unable to hold on, she slipped through the branches
and clutched my shoe. I never saw such an exaggerated case of the
chills. I stooped to see what ailed her. She wavered like an autumn leaf
to the ground. I leaped down, but she had limped under a bush and
suddenly got well. Of course I knew she was tricking me! But I never saw
higher skill in a feathered artist."
_Voice._--The simple, but pleasing song of the black-throated gray
warbler is described in Rathbun's notes as follows: "The song as
ordinarily sung consists of three rather quickly given notes, of a
somewhat lisping quality, that rise and fall but are alike in
construction and a closing fourth note that may slur upward with a
decided accent, or may fall. The real construction of this song is lost
unless the singer is close by, for then it will be found that each of
the first three notes is a double one. It is a clear and pleasing song,
of good carrying quality, and somewhat smooth when heard at a distance.
During the nesting season the males will be heard in song much of the
time during the day. The habit of the bird is to perch on or near the
top of a young evergreen tree and sing repeatedly without shifting its
perch, then to fly to another tree of similar character and repeat its
actions."
As I heard it in Washington, I wrote it _swee, swee, ker-swee,
sick_, or _swee, swee, swee, per-swee-ee, sic_. Dr. Walter P.
Taylor writes it in his notes _zee zeegle, zeegle, zeegle, zort,
tseeee_. Grinnell and Storer (1924) describe it as "a rather
lazy, drawling utterance, deep-toned rather than shrill.
_W[=e][=e]-zy, w[=e][=e]-zy, w[=e][=e]-zy, w[=e][=e]-zy-weet_;
_tsewey, tsewey, tsewey, tsewey-tsew_; _zu[=e][=e], zu[=e][=e],
zu[=e][=e], soop; s[)i][)i]]-w[=e][=e]zy, w[=e][=e]zy we-tsú_;
_ow[=e]z[=e]-w[=e]z[=e]-w[=e]z[=e]-w[=e]z[=e]-ch[=u]r_, are
syllabifications written by us at different times when individual birds
were singing close at hand. There are modifications in the song;
sometimes the terminal syllable is omitted and again only three of the
two-syllabled notes are given. The ordinary call is a rather low,
one-syllabled _chit_."
Mrs. Bailey (1902) says that "its song is a simple warbler lay,
_zee-ee-zee-ee, ze, ze, ze_, with the quiet woodsy quality of _virens_
and _caerulescens_, so soothing to the ear." Bowles (1902) heard an
unusual song that "was on the principle of a yellow-throated vireo or a
scarlet tanager; but the quality of a blue-headed vireo in addition,
making a very strong and rich song."
_Field marks._--The gray back, white breast with a few black streaks,
two white wing bars, and, particularly, the conspicuous black and white
pattern of the head and throat will make this warbler almost
unmistakable. The tiny yellow spot in front of the eye is visible only
at close quarters. Young birds and adults in the fall show the same
characters more or less obscured by brownish edgings. The female has a
white throat instead of a black one.
_Enemies._--Jays of different species and crows evidently take heavy
toll of the eggs and young, as they are persistent nest hunters and
often have their own broods to feed near by. Bowles (1902) says that
"one pair of California jays seemed to have located every nest that was
built in a gulch where they were building their own nest." One of the
Grinnell and Storer (1924) party "interrupted an attack by a California
Striped Racer upon a brood of Black-throated Gray Warblers. The female
parent was much excited, flying from twig to twig, calling, and
fluttering her wings. Near by, on the ground, was one of the young
warblers. There was good evidence that the snake had already swallowed
another member of the brood." This warbler seems to have escaped any
interference by cowbirds.
_Fall._--The southward migration begins in September and is mainly
accomplished during that month; Washington is generally vacated during
September, but migration continues through California during the first
half of October; after the middle of October even southern California is
deserted, and the black-throated gray warblers have gone to their winter
haunts in Mexico.
DISTRIBUTION
_Range._--Western North America from central British Columbia to
southern Mexico.
_Breeding range._--The black-throated gray warbler breeds =north= to
southwestern British Columbia (Hagensborg and Lillooet). =East= to
southwestern British Columbia (Lillooet and Chilliwack); western
Washington (Bellingham and Leavenworth); central northern Oregon (The
Dalles); possibly southwestern Idaho (Riddle); southwestern Wyoming,
possibly (Mountain); western and southern Colorado (probably Escalante
Hills, Coventry, and the Culebra Range); central New Mexico (Santa Fe);
and northeastern Sonora (San Luis Mountains). =South= to northeastern
Sonora (San Luis Mountains); southeastern to north-central Arizona
(Huachuca Mountains, Santa Rita Mountains, Santa Catalina Mountains, and
Bill Williams Mountain); and northeastern Baja California (Sierra San
Pedro Mártir). =West= to northern Baja California (Sierra San Pedro
Mártir); western California (San Jacinto Mountains, Glendora, Santa
Lucia Peak, and Lakeport); western Oregon (Kirby, Coos Bay, Corvallis,
and Portland); western Washington (Spirit Lake and Shelton); and
southwestern British Columbia (Victoria, Stuart Island, and Hagensborg).
_Winter range._--The principal winter home of the black-throated gray
warbler is in western Mexico. It is found in winter =north= to extreme
southern Arizona (Yuma, occasionally in the Baboquivari Mountains, and
Tucson). =East= to southeastern Arizona (Tucson); eastern Sonora (Tesia
and Alamos); southwestern Durango (Chacala); northern Michoacán
(Patambán); Mexico (city of Mexico); and central Oaxaca (Oaxaca).
=South= to central Oaxaca. =West= to western Oaxaca (La Parada);
Guerrero (Chilpancingo); western Michoacán (Los Reyes); southern Sinaloa
(Escuinapa and Mazatlán); southern Baja California (Victoria Mountains
and San José del Rancho); and southwestern Arizona (Yuma). It has also
been found at this season casually, south to Dueñas, Guatemala, and
north to Pasadena and Eureka, Calif., and Cameron County, Tex.
_Migration._--Early dates of spring arrival are: New Mexico--Cooney,
April 6. Arizona--Santa Rita Mountains, March 21. California--Grass
Valley, March 24. Oregon--Portland, April 14. Washington--Tacoma, April
10. British Columbia--Chilliwack, April 16.
Late dates of fall departure are: British Columbia--Courtenay, September
7. Washington--Yakima, October 27. Oregon--Eugene, October 11.
California--Diablo, November 11. Arizona--Phoenix, November 8.
_Casual records._--A black-throated gray warbler was picked up dead at
Lenox, Mass., on December 8, 1923. A specimen was collected at Ithaca,
N. Y., on November 15, 1936. On December 8, 1941, an individual was
observed on Bull's Island, S. C.; and from December 26, 1942, to January
5, 1943, one was under observation at Miami, Fla.
_Egg dates._--Arizona: 12 records, May 4 to June 19; 7 records, May 17
to 26.
California: 32 records, May 1 to July 3; 18 records, May 20 to June 10,
indicating the height of the season.
Washington: 8 records, May 29 to June 28; 5 records, June 5 to 23
(Harris).
DENDROICA TOWNSENDI (Townsend)
TOWNSEND'S WARBLER
HABITS
This warbler always reminds me of our familiar black-throated green
warbler, which it resembles slightly in color pattern but more
particularly in its habits and its drowsy song. Its voice is as much
associated with the northwestern forests of tall firs as is that of our
eastern bird with the pine woods of New England. Its breeding range is
confined to the coniferous forests from Prince William Sound and the
upper Yukon in Alaska south to Washington and east to southwestern
Alberta and western Montana, but it is better known as a migrant through
the Rocky Mountain region in general and as a winter visitant in
California.