Oregon--Thurston, October 5. California--Eureka, October 12.
Wyoming--Yellowstone Park, August 25. North Dakota--Fargo, September 8.
South Dakota--September 15. Nebraska--Fairbury, September 30.
Kansas--Lawrence, September 26. Oklahoma--Oklahoma City, October 12.
Texas--Somerset, October 10. Iowa--Grinnell, September 6. Missouri--St
Louis, September 17. Illinois--Chicago, August 31. Indiana--Hobart,
September 2. Ohio--Austinburg, August 25. Kentucky--Bowling Green,
September 14. Tennessee--Athens, October 3. Arkansas--Rogers, October 4.
Louisiana--Monroe, September 26. Mississippi--Edwards, September 22. New
York--Rhinebeck, August 31. Pennsylvania--Pittsburgh, September 8.
District of Columbia--Washington, September 9. West Virginia--Bluefield,
September 12. Virginia--Naruna, September 22. North Carolina--Mount
Mitchell, September 30. South Carolina--Spartanburg, September 21.
Georgia--Round Oak, October 10. Alabama--Anniston, October 8.
Florida--New Smyrna, October 4. Bahamas--Cay Lobos, November 22.
Cuba--Habana, November 17. Dominican Republic--San Juan, October 1.
Puerto Rico--Mayagüez, December 14. Costa Rica--Carrillo, October 2.
_Banding._--The myrtle warbler comes rather more readily than other
warblers to banding traps, especially in winter, and so has yielded
several records of migration and of longevity for return to the place of
banding. A myrtle warbler banded at Elmhurst, Long Island, on October
19, 1936, was recovered on December 9, 1936, at Awensdaw, S. C. One
banded on October 2, 1932, at Fargo, N. D., was found dead December 5,
1932, at Clarence, La. Another banded at Wilton, N. D., on September 25,
1939, was found in January 1940 at Leola, Ark. One banded on February 2,
1930, at Gastonia, N. C., was shot on December 25, 1930, at Kings Creek,
Cherokee County, S. C.
A banding station at Thomasville, Ga., obtained several records
indicative of the birds' tendency to return to the same wintering place.
Three birds banded in March 1920, were retrapped in February and March
of 1921. One banded February 24, 1921, was retrapped February 5, 12, and
13, 1924, and found dead, apparently of starvation, on the fifteenth. A
myrtle warbler banded on February 28, 1917, was retrapped in March 1920
and several times between March 1 and 17, 1921. It was then at least 5
years old and had made four round trips to the breeding grounds.
Another myrtle warbler banded at Huntington, Long Island, on October 23,
1933, was killed February 1, 1940, at Dunbar, S. C.; it was then at
least 6-1/2 years old.
_Casual records._--At least six specimens of the myrtle warbler have
been collected in Greenland: Fiskenaes, May 21, 1841; Julianehaab, about
1847; Godhavn, July 31, 1878; Nanortalik, May 23, 1880; Agpamiut, in
Sukkertoppen District, October 15, 1931; and Kangea, near Godthaab,
October 28, 1937. A specimen was taken from the stomach of a white
gyrfalcon October 7, 1929, killed near the Post on Southampton Island.
Two specimens have been collected on the Arctic Coast of Alaska: one on
June 3, 1898, at Point Tangent; and one June 4, 1930, near Point Barrow.
A myrtle warbler was collected May 25, 1879, on the northeast coast of
Siberia at latitude 67° N. At sea about 100 miles from Cape Hatteras,
several myrtle warblers were noted on October 16 and 31, 1930.
_Egg dates._--Maine: 16 records, May 26 to June 23; 10 records, June 11
to 20, indicating the height of the season.
New Brunswick: 10 records, June 5 to 28; 6 records, June 13 to 21.
Nova Scotia: 14 records, May 23 to June 21; 7 records, June 3 to 17
(Harris).
DENDROICA CORONATA HOOVERI McGregor
ALASKA MYRTLE WARBLER
HABITS
The Alaska myrtle warbler is another subspecies that was described many
years ago but only recently admitted to the A. O. U. Check-List. Richard
C. McGregor (1899) described this warbler, from specimens collected in
California, as a western race and named it for his friend Theodore J.
Hoover, who collected the type and placed his material at his disposal.
He called it _Dendroica coronata hooveri_, Hoover's warbler. In his
description of it he says that it is "in colors and markings like
_Dendroica coronata_, but with wing and tail much longer." His table of
measurements shows that the wings of California males average .15 inch
longer than those of eastern birds, and the tails .14 inch longer, less
than 1/6 inch! Among the wing measurements of eastern males the
individual variation is as great as the difference in his averages, the
shortest measuring 2.80 and the longest 2.95 inches! It appears to be a
quite finely drawn subspecies.
Dr. Oberholser (1938) says of it: "The Myrtle Warblers breeding in
Alaska are recognizable as a western race of this species. They differ
from the eastern bird in larger size and more solidly black breast in
the male. The upper parts in winter plumage and in the young are also
less rufescent than in the eastern bird."
The breeding range of this race, so far as known, extends from
northwestern Mackenzie to western Alaska, and southward to central
British Columbia and central Alberta. It has been found in winter from
California to southeastern Louisiana, in the southeastern United States,
and in northern Baja California and in southern Veracruz, in Mexico. It
may be commoner than is supposed, as it is recognizable only with
specimens in hand.
Dr. Joseph Grinnell (1900) writes of its habits in northern Alaska:
Hoover's Warblers were numerous summer residents of the timber tracts
throughout the Kowak Valley from the delta eastward. In the latter part
of August scattering companies were frequenting the spruce, birch and
cottonwoods, among the foliage of which they were constantly searching,
with oft-repeated 'chits,' just as are their habits in winter in
California. The last observed, a straggling flock of six or eight, were
seen in a patch of tall willows about sunset of August 30th. The
following spring the arrival of Hoover's Warblers was on May 22nd. They
were already in pairs and the males were in full song. At this season
they were confined exclusively to the heavier spruce woods. In the Kowak
delta, on the 23rd of June, a set of five considerably-incubated eggs
was secured. The nest was in a small spruce in a tract of larger growth,
and only four feet above the ground. It is a rather loose structure of
fine dry grass-blades, lined with ptarmigan feathers.
In the Atlin region of northern British Columbia, according to Mr.
Swarth (1926), it is a common species, breeding mostly in the lowlands:
A nest with five fresh eggs (Mus. Vert. Zool. no. 1992) was taken by
Brooks on June 15. It was in a slender spruce, one of a small thicket in
a locality that is largely poplar grown, about forty feet from the
ground and near the top of the tree. It rested on the twigs forming the
terminal forks of a branch, about three feet from the trunk. The outer
walls of the nest were built mostly of the shredded bark of the
fire-weed stalks, with a little fire-weed 'cotton,' some coarse grass
and small twigs, and several wing and tail feathers of a small bird. In
the lining there was some horse hair, mountain sheep hair and a few soft
feathers.
Another nest, containing newly hatched young on June 28, was in a small
jack pine in open woods on the shore of Lake Atlin.
During the last week in August and the first week in September the
southward exodus was at its height. Flocks of warblers, mostly this
species, flitted rapidly through the poplar woods, and there was a
constant stream of myrtle warblers making long flights overhead. The
last one, a single bird, was seen September 19.
As the breeding ranges of Hoover's warbler and Audubon's warbler
approach each other in British Columbia and may even overlap it would
not be strange if hybrids between these two closely related species
should occasionally turn up. Joseph Mailliard (1937) calls attention to
a number of such hybrids between both forms of _coronata_ and
_auduboni_. And more recently, Fred M. Packard writes to me: "I have
inspected skins in most of the major museums in America to detect these
hybrids, and have been surprised at the number I have found. All but two
were taken in the Rockies or farther west, so that presumably the
subspecies concerned is _D. c. hooveri_."
DENDROICA AUDUBONI AUDUBONI (Townsend)
PACIFIC AUDUBON'S WARBLER
PLATE 34
HABITS
The Pacific Audubon's warbler is a handsome western species closely
related to our familiar myrtle warbler, which to a large extent it
replaces, and is much like it in behavior and appearance; but it has one
more touch of color in its brilliant yellow throat, five spots of yellow
instead of four, and it has more white in the wings and tail. Although
its breeding range does not extend nearly as far north as that of the
myrtle warbler, it extends farther south, and to considerably higher
altitudes, breeding largely in the Canadian Zone among the pines,
firs, and spruces. Including the range of the Rocky Mountain form
(_memorabilis_), which has not yet been admitted to the A. O. U.
Check-List, the type race breeds from central British Columbia, central
Alberta, and west-central Saskatchewan southward to southern California,
northern Arizona, New Mexico, and western Texas. Throughout most of this
range it is widely distributed in the lowlands only during the winter,
retiring to the mountains for the breeding season.
In the mountains of New Mexico it has been found breeding at altitudes
of from 7,500 feet to over 11,000 feet. In Colorado it breeds at similar
elevations and perhaps up to nearly 12,000 feet. In southern California,
Dr. Joseph Grinnell (1908) found it breeding in the San Bernardino
Mountains from 9,000 feet "almost to timber limit, 10,500 feet
elevation, at least. * * * This was one of the most abundant birds of
the San Bernardino mountains, and was widely distributed from the lower
edge of the Transition zone up through the Boreal." Grinnell and Storer
(1924) write:
The Audubon Warbler is the most widely distributed and the most abundant
of all the species of wood warblers found in the Yosemite region. It
occurs in numbers throughout the main forested districts of the
mountains during the summer season, and it frequents the deciduous trees
and brush of the foothill and valley country in the winter time.
Altitudinally its summer range extends from the beginning of the
Transition Zone yellow pines on the west slope, at 3300 to 3500 feet, up
through the lodgepole pines and other conifers of the Canadian and
Hudsonian zones to the upper limit of unstunted trees at 10,000 feet or
a little higher. * * *
During the summer season the Audubon Warbler keeps mainly to coniferous
trees, foraging from 10 to 50 feet or more above the ground. In the
Transition Zone and part of the Canadian Zone it shares this habitat
with the Hermit Warbler, but at the higher altitudes it is the only
warbler present in the evergreen forest.
Farther north, in Mono County, Calif., James B. Dixon tells me that he
found it nesting between 7,600 and 9,500 feet elevation. Referring to
the Toyabe region in Nevada, Dr. Jean M. Linsdale (1938) found the Rocky
Mountain form in a somewhat different environment: "In the mountains the
area occupied by this warbler agreed fairly well with the area covered
with trees. Individuals were seen most often in aspens, limber pines,
birches, willows, and mountain mahoganies." Angus M. Woodbury (MS.) says
of the breeding range of the Rocky Mountain form in Utah: "It summers in
altitudes ranging from about 7,000 to 10,000 feet and nests in almost
any of the components of the forests in those altitudes; pine, fir,
spruce, aspen, or oak."
In Washington, Audubon's warbler is common and well distributed from
near sea level in the vicinity of Seattle and Tacoma up to about 8,000
feet in the mountains. Near Tacoma, D. E. Brown showed us some typical
lowland haunts of this warbler in the so-called "prairie region." On
this smooth, flat land, a fine growth of firs and cedars was scattered
about in the open; the two or three local species of firs were most
abundant and were growing to perfection, being well branched down to the
ground.
_Spring._--There is a northward as well as an altitudinal migration in
the spring. Samuel F. Rathbun says in his notes from Seattle: "Although
the Audubon's is of frequent if not regular occurrence during the
winter, a migration of the bird through the region is to be noted each
spring and fall." Near Seattle the first birds are seen and their song
is heard about March 10 to 15, and numbers are seen passing through up
to the latter part of April. "By way of comparison, in the Lake Crescent
section the first are seen about April 2, at the earliest, and after
three weeks the last appear to have passed by, as the species performs
its spring migration in a leisurely manner." A later wave of migrants
passes through Seattle between April 10 and 25, probably birds that nest
farther north.
Migration is evident in Utah, for Woodbury (MS.) says: "In addition to
its summer residence, it is a common migrant through the state, and a
sparse winter resident, mainly at low altitudes. It migrates through the
streamside and cultivated trees of the valleys, including shade trees
and orchards. The migrations cover a period of about 6 weeks each in
spring and fall, usually from about mid-April to the end of May and from
mid-September to the end of October, but in different years the waves
may be a little earlier or later."
In California, there is a gradual exodus of Audubon's warblers from the
lowlands to the mountains during April and May. Mrs. Amelia S. Allen
tells me that "by the end of April they have disappeared from the San
Francisco Bay region." And Swarth (1926b) says that in May, following
the spring molt, "there is a gradual withdrawal of the birds to the
higher mountains and to more northern latitudes."
Audubon's warbler occurs abundantly on the Huachuca Mountains, Ariz.,
but as a migrant only, during March, April, and May. Swarth (1904)
writes:
Though distributed over all parts of the mountains, they were at all
times more abundant in the higher pine region, than elsewhere; and on
April 24, 1903, I found them particularly numerous along the divide of
the mountains, evidently migrating. They could hardly be said to be in
flocks on this occasion, for along the ridge, which runs almost due
north and south, there was for several miles a continuous stream of
Audubon Warblers travelling rapidly from tree to tree, always moving in
a northerly direction; sometimes a dozen or more in one pine, and
sometimes only two or three, but never stopping long and all moving in
the same direction. Almost all that were seen on this occasion were high
plumaged males, hardly half a dozen females being observed for the day.
This was about two weeks before the local breeding race _(D. a.
nigrifrons)_ might be expected to arrive.
Dr. Merrill (1888), at Fort Klamath, Oreg., found Audubon's warblers
"extremely abundant during the migrations. A few males were seen at
Modoc Point on the 8th and 9th of April, and at the Fort on the 15th; by
the 20th they were quite plentiful. A second 'wave' composed of both
males and females, which latter had not previously been seen, arrived
about the 4th of May, when they suddenly became more abundant than ever,
bringing _D. aestiva morcomi_ and _H. lutescens_ with them."
_Nesting._--The only two nests of Audubon's warbler that I have seen
were shown to me in Washington, near the State University at Seattle.
The University is located on high land at the north end of Lake
Washington, where the steep banks, sloping down to the lake, are heavily
wooded with a mixed growth of large and small firs of at least two
species, as well as cedars, alder trees, and maples. In the more open
part of the woods I was shown, on April 29, 1911, a nest of this warbler
placed about 30 feet from the ground on two small branches and against
the trunk of a tall Douglas fir beside a woodland path. The other nest I
saw in the previously described "prairie region" near Tacoma on May 14,
1911; it was placed only 9 feet from the ground but 10 feet out from the
trunk of a dense Douglas fir growing in the open, and was well concealed
in the thick foliage.
These nests were evidently typical for the region, according to Rathbun.
He mentions in his notes two other nests. One, found May 2, 1909, on
the east side of Lake Washington and along a road, was 30 feet from the
ground in a small hemlock, near the extremity of one of the limbs and 7
feet out from the trunk. The other, found May 11, 1913, was in a small
fir about 30 feet up and about 4 feet from the trunk on one of the lower
limbs. "The nest is a very beautiful structure, constructed outwardly of
very small twigs from the fir or hemlock, inside of which are placed
smaller ones of the same character, with black rootlets, and lined with
feathers, of which a quantity are used, and a few horsehairs. It is a
compactly built affair." Dawson and Bowles (1909) say that the nests are
placed from 40 to 50 feet up, and usually measure 4 inches in width
outside by 2-3/4 in depth; and inside 2 by 1-1/2 inches. They are made
externally of such materials as fir twigs, weed tops, flower pedicels,
rootlets, and catkins, and are heavily lined with feathers of various
birds--including grouse, ptarmigan or domestic fowls--these feathers
often curving upward and inward so as partially to conceal the eggs.
Dr. J. C. Merrill (1898) found a very different type of nesting near
Fort Sherman, Idaho: "Here a majority of the nests I found were in
deciduous trees and bushes, generally but a few feet from the ground.
One was in a small rose bush growing at the edge of a cut bank
overhanging a road where wagons daily passed close to it. * * *
Occasionally one was seen in deep woods by the roadside near where hay
had been brushed off a load on a passing wagon; this was utilized for
the entire nest except lining, making a conspicuous yellow object in the
dark green fir or pine in which it was placed."
P. M. Silloway (1901) found a nest of Audubon's warbler near Flathead
Lake, Mont., that was 18 feet from the ground in a fork of a willow.
"The fork containing the nest was in a main stem, upright, a number of
feet below the leaf-bearing part of the tree, so that the nest was
exposed quite fairly to view." H. D. Minot (1880) found one at Seven
Lakes, Colo., in an odd situation: "The nest, composed of shreds and
feathers, with a few twigs without and hairs within, was built in a
dead, bare spruce, about twenty feet from the ground, compressed between
the trunk and a piece of bark that was attached beneath and upheld
above, where a bough ran through a knot-hole, so compressed that the
hollow measures 2-1/4 x 1-3/4, and 1-1/2 inches deep." Dr. Chapman
(1907) describes a nest from Estes Park, Colo., as "loosely constructed
of weed-stems and tops, and strips of bark, lined with fine weeds and
horse-hair."
Mr. Woodbury (MS.) describes Utah nests as "compactly woven, cup-shaped
structures, usually of fine grasses, plant fibers or shredded bark,
lined with feathers or some substitute, and camouflaged with some fine
stringy material holding bracts or other small particles in place." He
reports nests in such conifers as spruce, balsam, and ponderosa pine,
and in aspen and oak.
J. Stuart Rowley writes to me: "In California, I have found several
nests of this species in the San Bernardino Mountains and in the Mono
County area in the northern part of the State. The nests I have found
have all been beautifully made structures, securely fastened to small,
low hanging branches of lodgepole pine, and placed about 10 to 12 feet
from the ground."
Dr. Grinnell (1908) records three nests, found in the San Bernardinos;
one "was twenty feet above the ground in the thick foliage of a short
drooping fir bough. It was compactly composed of weathered grasses,
frayed-out plant fibres, and tail and wing feathers of juncos and other
small birds. Internally it was thickly lined with mountain quail
feathers, some of the chestnut-colored ones sticking above the rim
conspicuously. This feather feature seems to be characteristic of
Audubon warblers' nests, as it was noticeably present in all that we
saw." Another nest was 25 feet from the ground in one of the lowest
branches of a yellow pine. The third "was snugly tucked away in a small
clump of mistletoe on an alder branch twelve feet above the ground."
J. K. Jensen (1923) says of New Mexico nests: "The nests are usually
placed on a horizontal limb of a pine or spruce, but also among dead
twigs on the trunks of cottonwoods, and even in a cavity of some tree.
All nests found were lined with a few feathers of Bluebirds and
Long-crested Jay."
Nests in tamarack, cedar, and birch have been reported by other
collectors.
_Eggs._--Audubon's warbler lays from 3 to 5 eggs, almost always 4. They
are ovate, tending toward short ovate, and are slightly glossy. They are
grayish or creamy white, spotted and blotched with "raw umber,"
"Brussels brown," "argus brown," and sometimes "auburn," with underlying
spots of "pale brownish drab," "light brownish drab," or "light mouse
gray." The markings are often confined to the large end, and frequently
the drab undertones are in the majority, sometimes running together to
form a cap, and this is relieved with a few superimposed spots or
blotches of dark "argus brown," or scattered small scrawls so dark as to
appear almost black. The eggs generally are sparsely but rather boldly
marked. The measurements of 50 eggs average 17.6 by 13.5 millimeters;
the eggs showing the four extremes measure =19.4= by 14.0, 19.1 by
=14.5=, and =15.4= by _12.3_ millimeters (Harris).
_Young._--The period of incubation is probably between 12 and 13 days,
as with the Myrtle warbler. Mrs. Wheelock (1904) writes:
In the brood whose incubation was closely watched, I found that twelve
days elapsed between the laying of the last egg and the advent of the
young. The female did most of the brooding; the male was found on the
nest only once, but was usually perched on a neighboring tree warbling
his enthusiastic little song, "cheree-cheree-cheree-cheree." After the
young were feathered enough to leave the nest, which occurred when they
were two weeks old, the male forgot to sing and became a veritable
family drudge with the brood ever at his heels clamoring for food. * * *
The pair whose young had hatched so early were very friendly, feeding
them without much fear while I sat within three or four feet of the nest
and on a level with it. They usually came with nothing to be seen in
their beaks, but the insect food they had gleaned and carried in their
own throats was regurgitated into the throats of the young. When the
latter were five days old the mother bird, for the first time, brought
an insect large enough to be seen, and crammed it into the open bill of
one of the nestlings, and from that time on most of the food brought was
eaten by the young while fresh.
The general opinion seems to be that two broods are often, perhaps
usually, raised in a season. The young birds are the first to leave
their mountain resorts, probably driven out by their parents, and are
the first to appear in the lowlands.
_Plumages._--The plumages and molts of Audubon's warbler are similar in
sequence to those of the myrtle warbler; in juvenal and first fall
plumages the two species are almost indistinguishable, though there is
always more white in the tail feathers of the western bird, in which the
white spot usually reaches the fourth feather even in young birds. In
any plumage the white areas in the tail of Audubon's warbler occupy two
more feathers on each side of the tail than in the myrtle warbler.
The juvenal Audubon's warbler is brown above, streaked with black and
white, and white below, streaked with black; the sexes are alike. This
plumage is worn but a short time; Dr. Grinnell (1908) says that it "is
of very short duration, not more than fifteen days, I should say"; and
Swarth (1926) says that is "worn but a few weeks. Tail and wing have
scarcely attained full length when the first winter plumage begins to
appear, and by the time the birds are drifting back into the lowlands in
September the last vestige of the juvenal plumage is gone." This
postjuvenal molt involves all the contour plumage and the wing coverts,
but not the rest of the wings or the tail.