hudsonicus_) was observed to approach the blind, coming to within seven
feet of the nest. At this time, the female simply left the vicinity of
the nest at once and gave no alarm notes. Later the same day, when a
young Black and White Warbler approached the nest to a distance of five
feet, the female pounced upon it and struck with considerable force.
When the intruder returned a second time the female flew at it and drove
it away. The indifference to red squirrels and at the same time the
offensive reaction toward small passerine intruders (_Vireo olivaceus_
and _Penthestes atricapillus_) has also been noted by the Nices (1932:
160).
Reading and Hayes (1933) write: "While at the nest, we noticed an
inquisitive Chestnut-sided Warbler in a maple a short distance away. He
hung around for several minutes, peering at us, until suddenly the male,
ably seconded by his mate, attacked him and drove him off. A male
Blackburnian met the same fate a little while later, while peacefully
hunting insects in the big spruce and, about an hour after that a
Red-eyed Vireo changed his intended route at the first warning note and
promptly withdrew. Curiously enough, a small family of Black-capped
Chickadees travelling slowly through the spruce was totally
disregarded."
The black-throated green warbler is seldom bothered by the cowbird,
although mentioned by several writers as imposed upon.
_Voice._--Aretas A. Saunders has sent me the following full account of
the two songs of the black-throated green warbler: "The quality of the
songs is sweet and musical and exceedingly pleasing. With the possible
exception of the yellow warbler, this species has the most attractive of
the _Dendroica_ songs. The quality has something indescribable that is
all its own and enables those familiar with it to recognize the song,
however variable the form.
"The black-throated green warbler has two distinct forms of song. Both
may be sung by the same individual, and both are equally common in the
migration and through the nesting season, so that they cannot be
considered as territory and nesting songs. I distinguish them as first
and second, but my choice is purely arbitrary. Both are delivered in the
same quality. The first is a little longer than the second, for it
contains more notes; but it is not proportionately longer, for the notes
are shorter.
"The first song has notes on three different pitches. The first notes,
three to nine but commonly four or five, are all on the same pitch,
usually the highest; the next note, usually a major third lower, is the
lowest; the next, and last, is between them. Such a song might be
written _sree sree sree sree sree tro tray_, all the notes being of
equal length. I have 34 records of this song, 23 of which follow this
form. A few are arranged with the last note highest, or lowest, or on
the same pitch as the first. The first notes are sometimes varied by
alternating short and long notes or sometimes are united in a long
trill.
"The second song consists of four or five notes only, with a definite
time arrangement--3 2 1 1 or 3 2 1 1 1; that is, the first note is three
times as long as the last and the second note twice as long. The third
and fourth notes are on the same pitch, but the others are on different
pitches, so that the song might be written _treee tray to to_, or a
5-note song _treee tray tray to-to tay_. The notes, as in the first
song, are on three different pitches, but they vary in every possible
way as to which note is highest and which lowest, so that there are six
possible arrangements of these different pitches in a 4-note song where
the last two notes are always on the same pitch. In my collection of 52
records of this song I have samples of all six, and of these 33 are of
four notes, while only 19 have the fifth note added.
"Songs of this species vary from 1-1/5 to 2 seconds in length, the first
song from 1-2/5 to 2 seconds, and the second 1-1/5 to 1-4/5 seconds. The
pitch varies from F´´´to E´´´´, a half tone less than an octave. One
peculiar song of the first type, however, was prefixed by a wren-like
chatter that was pitched on B´´, but the remaining song was normal in
pitch. Single songs average about one and a half tones in range, but the
majority of the songs of the first type range two tones, and those of
the second type two and a half tones.
"The song is to be heard from the first arrival of the species in
migration until shortly after the first of August. In 14 seasons the
average date of late song in Allegany State Park is August 2, the
earliest is July 25, 1927, and the latest August 11, 1935 and 1937.
While there is no regular revival of full song after the molt, there is
occasional singing of a primitive character."
C. Russell Mason tells me of a song in which the high, musical note was
given six times instead of the usual once. Francis H. Allen has heard
some variations in the songs and has sent me these notes: "One bird
added at the end of the familiar _zee zee zee zoo zee_ a coda of an
intricate and wrenlike quality, and sang this beautiful song constantly.
Another introduced a trill after the second note of the 'trees, trees'
song and ended it with a low note. Another bird sang a variant of the
'trees, trees' song, in which it substituted for the final high note a
lower-pitched _su-eet su-eet_ without the familiar _z_ quality." He and
Dr. W. M. Tyler heard one that "sang in addition to one of the
characteristic songs of the species an entirely unrecognizable one that
went something like _ti-ti-ti-ti-ti-zp_. The first five notes were very
thin and slight with a very short pause before the last one, and the
final note was a short emphatic buzz. Once this song ran into a
characteristic song without a pause between." He refers to the ordinary
call-note as a distinctive _chet_, suggesting that of the myrtle
warbler, but thinner. "On the occasion in early June, I heard from a
male bird a succession of chippering notes which I had formerly
attributed to the young alone. He alternated these notes with singing."
Many other somewhat similar renderings have appeared in print, both in
syllables and in human words, most of which seem to recall the song to
mind. Some of the best of the wordings are _trees, trees, murmuring
trees_ and _sleep, sleep, pretty one, sleep_ (Torrey, 1885); _good Saint
Theresa_ (Maynard, 1896); and _take it, take it, leisurely_ (Stanwood,
1910b). Miss Stanwood pays this tribute to the charm of the song: "His
voice is suggestive of the drowsy summer days, the languor of the breeze
dreamily swaying the pines, spruces, firs, and hemlocks. It recalls the
incense of evergreens, the fragrance of the wild strawberry, the
delicate perfume of the linnea. No other bird voice is so potent to
evoke that particular spell of the northern woods."
The black-throated green warbler is a most persistent singer. The Nices
(1932) say that the first warbler "gave 466 songs in a single hour and
more than 14,000 in the 94 hours of observation." According to Albert R.
Brand (1938), the approximate mean number of vibrations per second in
the song is 6,025, in the highest note 6,750 and in the lowest note
5,125. This compares with a mean of 8,900 for the black-polled warbler,
which is the shrillest passerine bird song.
_Field marks._--The conspicuous, bright yellow cheeks, the olive-green
back, the prominent black throat, the two white wing bands, and the
white outer webs of the lateral tail feathers will distinguish the male
in breeding plumage. The female is duller and has less black, or none at
all, on the throat. Young birds in the fall are much like the female.
See the descriptions under Plumages.
_Fall._--The fall migration of the black-throated green warbler begins
during the latter part of August, continuing through September and often
through much of October. It seems to be a reversal of the route followed
in the spring. Similar haunts are frequented in the fall in the company
of vast congregations of other species. A remarkable flight of various
species of warblers was seen by Rev. W. F. Henninger in Scioto County,
Ohio, an account of which is quoted by W. L. Dawson (1903) as follows:
On September 28, 1899, I ran into a company of warblers which I would
place conservatively at two thousand individuals. It was like a regular
army as it moved up a long sloping hillside, and with wonderful
rapidity. The wind was blowing almost a gale from the north, and the
birds allowed themselves to be urged before it in the direction of their
ultimate retreat, like half-stubborn autumn leaves. Lisping, chipping,
whirling, driving, they hurried on and I after at full speed, panting,
and wishing devoutly for a better chance to identify the fleeing forms.
Arrived at the top of the hill the army suddenly halted and when I
arrived breathless I had time to note the arrangement by species, not
rigid indeed, but sufficiently striking to command attention. In the
center were seen Hooded Warblers and a sprinkling of Chestnut-sides. On
either side of these in turn were Black-throated Greens and Sycamores,
about two hundred of each; while the wings proper were held by
Bay-breasts and Black-polls in enormous numbers. * * * As the birds
deployed to feed the specific lines were not quite obliterated.
_Winter._--The following notes are contributed by Dr. Alexander F.
Skutch: "The black-throated green warbler is an abundant winter resident
in the Central American mountains, where it is well distributed on both
the Caribbean and Pacific slopes. In Guatemala, it winters from 1,000 to
about 8,500 feet above sea-level, but is not abundant at either of these
extremes of altitude. Farther south, in Costa Rica, it prefers slightly
higher elevations. Here I have not recorded it between 2,000 and 2,900
feet, although the greater part of my bird-watching in the country has
been done in this altitudinal belt. From 2,900 feet, where it is rare as
a winter resident, it ranges up to nearly 10,000 feet. At this
elevation, I found it abundant on the Volcán Irazú in late November.
Less sociable than the Townsend warbler, it does not form flocks, and
except during the actual period of migration, is more often seen alone
than in the company of others of its kind.
"As a rule the black-throated green warbler arrives late, and has rarely
been recorded before mid-October. But on August 9, 1933, I found a lone
male in full nuptial plumage with a mixed flock of small resident birds
in an open oak wood on the Sierra de Tecpán in the Guatemalan highlands.
He sang his dreamy, unsubstantial song as he foraged along with his
newly found companions. I saw only one other of his kind--or possibly it
was the same individual again--before early October, when the species
began to arrive on the Sierra de Tecpán in numbers.
"Another early arrival appeared on September 28, 1938, in the yard of
the cottage I occupied at Vara Blanca, at an altitude of 5,500 feet on
the northern slope of the Cordillera Central of Costa Rica. During the
following days, it came every afternoon to forage in the low cypress
hedges that surrounded the dwelling. Possibly it was attracted to these
because of associations with its native land, for these trimmed
cypresses were the only coniferous trees in the vicinity--indeed, in
Costa Rica, the warblers find no native conifers save two species of
_Podocarpus_, a genus whose center of distribution is in the Southern
Hemisphere rather than in the North. At times the newly arrived warbler
descended to the bare ground in the flower garden, where it appeared to
find something edible. On October 2 it was for the first time
accompanied by a second of its kind. Throughout the winter months a
black-throated green warbler continued to visit these cypress hedges.
"This is another migrant warbler that plucks the dainty white protein
corpuscles from the velvety cushions at the bases of the long petioles
of the Cecropia tree. In excessively humid highland regions, as at Vara
Blanca, the wide, hollow internodes of these trees are much of the time
flooded with water, and therefore uninhabitable by the Azteca ants which
at lower elevations usually colonize them. In the absence of the ants,
whose food these tiny morsels are, the birds find an abundance of them
on the Cecropia trees. A number of small native birds, including
finches, tanagers, warblers, honeycreepers and ovenbirds (Furnariidae),
share them with the migratory warblers.
"By mid-March the males are in resplendent nuptial plumage. On April 27,
1933, I heard a male black-throated green warbler singing among the
alder trees beside a rivulet on the Sierra de Tecpán. On April 4 and 5,
1938, a male sang repeatedly at the edge of the forest at Vara Blanca;
and from this date until the disappearance of the species from the
region on April 14 I often heard their song.
"There is a certain amount of evidence that with the increasing aridity
of the dry season the black-throated green warblers withdraw early in
the year from districts on the Pacific slope where they were present
during the wetter closing months of the preceding year. Thus, on the
Sierra de Tecpán I met none between December 7 and April 20, when the
northward movement was in progress, and the birds seen were doubtless
transients rather than winter residents. And in the higher parts of the
Basin of El General in southern Costa Rica I have recorded the species
only in October, November, and December, after which the nearly rainless
season begins. But in the wetter climate of Vara Blanca, they were seen
throughout February and March until their northward departure in April.
"The black-throated green warbler withdraws from Costa Rica about the
middle of April, and by the end of the first week of May has vanished
from Guatemala.
"Early dates of fall arrival in Central America are: Guatemala--passim
(Griscom), October 15; Sierra de Tecpán, August 9, 1933; Finca Mocá,
October 29, 1934. Honduras--Tela, October 26, 1930. Costa Rica--Vara
Blanca, September 28, 1937; San José (Underwood), October 16; Basin of
El General, October 22, 1936.
"Late dates of spring departure from Central America are: Costa
Rica--Juan Viñas (Carriker), April 17; Vara Blanca, April 14, 1938.
Guatemala--passim (Griscom), May 4; Sierra de Tecpán, May 6, 1933."
The following account of its winter haunts in El Salvador by Dickey and
van Rossem (1938) is also interesting:
All through the mountainous districts, both in the interior and
coastwise, the black-throated green warbler is an extremely common
winter visitant; in fact, it constitutes, at levels between 3,500 and
5,000 feet, fully 90 per cent of the nonresident warbler population. The
numerous flocks of from a dozen to half a hundred individuals invariably
formed the nuclei about which gathered smaller numbers of other
insectivorous species resident and nonresident. The black-throated green
warbler showed decided preference for the oak and pine association at
the altitudes mentioned, although it was by no means confined to such
environments.
Many were seen in the coffee cover down to 3,000 feet on Mt.
Cacaguatique and 2,300 feet at San Salvador. A few birds reach as high
as 8,000 feet, at which level they were found in both pines and cloud
forest on Los Esesmiles. * * * The average winter range of _virens_ lies
approximately 3,000 feet below that of _townsendi_, although strays and
vagrants make the extremes of altitude nearly the same in both cases.
DISTRIBUTION
_Range._--Eastern North America from southern Canada to Panamá.
_Breeding range._--The black-throated green warbler breeds =north= to
central western and northeastern Alberta (Grande Prairie, Peace River
and Chipewyan); central Saskatchewan (Big River and Emma Lake); southern
Manitoba (Brandon and Hillside Beach); southern Ontario (Lac Seul,
Rossport, Chapleau, and Lake Abitibi; casual or accidental at Moose
Factory); central Quebec (Mistassini Post, Upper St. Maurice River,
Godbout, Mingan, and Natashquan); and casually in southeastern Labrador
(Battle Harbor). =East= to southeastern Quebec (Natashquan);
southwestern Newfoundland (Spruce Brook and Tompkins); Nova Scotia
(Sydney, Halifax, and Barrington); the coast of New England; Long Island
(Miller's Place); northern New Jersey (Demarest and Dover); central
Pennsylvania (Pottsville and Carlisle); central Maryland (Thurmont);
central and southeastern Virginia (Charlottesville and Dismal Swamp);
North Carolina (Lake Mattamuskeet); and central South Carolina
(Charleston). =South= to South Carolina (Charleston); northern Georgia
(Pinelog Mountains and Lookout Mountain); northeastern Alabama (Sand
Mountain); southeastern Kentucky (Big Black Mountain and Jackson);
central Michigan (Bay City and Mason County); northern Wisconsin (New
London and Ladysmith); central Minnesota (Lake Minnetonka, Mille Lacs,
and Cass Lake); southwestern Manitoba (Aweme); and southern Alberta
(Brooks). =West= to western Alberta (Brooks, Glenevis, Sturgeon Lake,
and Grande Prairie).
_Winter range._--The black-throated green warbler is found in winter
=north= to southern Texas (Arroya Colorado, Willacy County); and Yucatán
(Tunkas and Chichén-Itzá). =East= to Yucatán (Chichén-Itzá); the coast
of Quintana Roo; northeastern El Salvador (Mount Cacaguatique); eastern
Costa Rica (Volcán Irazú); and central Panamá (Veragua); casual or
accidental to northern Colombia (one record; Cincinnati, Santa Marta
region). =South= to Panamá (Veragua and Volcán de Chiriquí). =West= to
western Panamá (Volcán de Chiriquí); western Costa Rica (El General);
western El Salvador (San Salvador); western Guatemala (Volcán de Agua
and Dueñas); Oaxaca (Tehuantepec); western Morelos (Curnavaca); Puebla
(Metlatoyuca); southern Tamaulipas (Altamira); probably eastern Nuevo
León (Linares); and southern Texas (Santa Maria and Arroya Colorado).
The black-throated green warbler has apparently extended its winter
range northward in recent years. Except for a single specimen taken at
Brownsville in January 1911, it was not known to winter in Texas until
1933-34, when about 30 birds were seen. Since then it has increased and
spread over most of Cameron County and to the southern border of Willacy
County. One was recorded on Bull's Island, S. C., on January 8 and 9,
1940.
The species is also rare or casual in winter or migration in the West
Indies: Cuba (Habana and Isle of Pines); Jamaica; Haiti (Île à Vache);
Puerto Rico (Adjuntas); and the islands of St. Croix, Guadeloupe, and
Dominica; also Watling Island, Bahamas.
The ranges as outlined apply to the entire species of which two
geographic races are recognized. The northern black-throated green
warbler (_D. v. virens_) is found in all the breeding range except the
coastal region, from southeastern Virginia to South Carolina, which is
occupied by Wayne's black-throated green warbler (_D. v. waynei_).
_Migration._--Late dates of spring departure from the winter home are:
Costa Rica--Juan Viñas, April 17. Guatemala--Tecpán, May 6.
Tamaulipas--Xicoténcatl, May 11. Cuba--Habana, May 1.
Early dates of spring arrival are: Florida--Key West, March 3.
Alabama--Eutaw, April 1. Georgia--Atlanta, March 26. South
Carolina--Mount Pleasant, March 22. North Carolina--Raleigh, March 22.
Virginia--Lawrenceville, April 3. West Virginia--French Creek, April 10.
District of Columbia--Washington, April 18. Pennsylvania--Erie, April
19. New York--Rhinebeck, April 20. Massachusetts--Cambridge, April 19.
New Hampshire--Tilton, April 26. Maine--Portland, April 26. New
Brunswick--Scotch Lake, May 1. Nova Scotia--Wolfville, May 3.
Quebec--Montreal, May 4. Louisiana--Avery Island, March 23.
Mississippi--Oxford, March 10. Tennessee, Chattanooga, March 19.
Kentucky--Eubanks, March 23. Arkansas--Delight, March 26.
Missouri--Forsyth, April 8. Illinois--Murphysboro, April 11.
Indiana--Bicknell, April 16. Ohio--Oberlin, April 13.
Michigan--Vicksburg, April 13. Ontario--Guelph, April 20.
Wisconsin--Milwaukee, April 19. Minnesota--Brainerd, April 25.
Texas--Rockport, February 5. Kansas--Independence, April 1. North
Dakota--Fargo, May 5. Manitoba--Aweme, April 30. Alberta--Edmonton, May
5.
Late dates of the spring departure of transients are:
Florida--Pensacola, May 7. Alabama--Long Island, May 16.
Georgia--Athens, May 14. South Carolina--Greenwood, May 17. North
Carolina--Chapel Hill, May 24. Virginia--Norfolk, May 26. West
Virginia--Fairmont, May 23. District of Columbia--Washington, June 10.
Pennsylvania--Beaver, May 27. Louisiana--Lobdell, May 9.
Mississippi--Horn Island, May 12. Tennessee--Knoxville, May 31.
Arkansas--Delight, May 30. Missouri--St. Louis, May 22.
Illinois--Chicago, June 3. Indiana--Notre Dame, June 2. Ohio--Toledo,
June 5. Texas--Brownsville, May 15. Oklahoma--Tulsa, May 18.
Kansas--Lawrence, May 16. Nebraska--Syracuse, May 27.
Early dates of fall departure are: Alberta--Glenevis, August 30.
Manitoba--Brandon, September 24. North Dakota--Fargo, September 19 (bird
banded). Nebraska--Stapleton, October 17. Oklahoma--Oklahoma City,
November 2. Minnesota--Minneapolis, November 2. Wisconsin--Madison,
November 1. Michigan--Detroit, November 1. Ontario--Ottawa, October 25.
Ohio--Columbus, October 31. Illinois--Rantoul, October 31.
Kentucky--Madisonville, October 24. Tennessee--Memphis, October 28.
Mississippi--Gulfport, November 18. Louisiana--New Orleans, November 4.
Newfoundland--Tompkins, October 4. Nova Scotia--Sable Island, October 7.
New Brunswick--Saint John, October 12. Quebec--Quebec, October 3.
Maine--Ellsworth, October 19. Vermont--Woodstock, October 19.
Massachusetts--Harvard, November 2. New York--Scarsdale, October 26.
Pennsylvania--McKeesport, October 25. District of Columbia--Washington,
October 21. North Carolina--Weaverville, October 31. Georgia--Athens,
November 1. Alabama--Fairhope, November 19. Florida--Sombrero Key,
November 10 (two struck lighthouse, one killed).
Early dates of fall arrival are: North Dakota--Wilton, September 4.
Kansas--Lake Quivira, September 6. Oklahoma--Tulsa, August 13.
Texas--Cove, July 26. Ohio--Toledo, August 20. Indiana--Waterloo, August
14. Illinois--Chicago, August 15. Kentucky--Versailles, August 13.
Missouri--Montier, August 25. Arkansas--Winslow, August 13.
Tennessee--Memphis, August 7. Mississippi--Hernando, July 30.
Louisiana--Breaux Bridge, August 12. Pennsylvania--Pittsburgh,
August 20. District of Columbia--Washington, August 22. West
Virginia--Bluefield, August 29.--Virginia--Charlottesville, September 3.
North Carolina--Montezuma, August 27. Georgia--Atlanta, September 6.
Florida--Pensacola, September 9. Cuba--Habana, September 30.
Mexico--Cuernavaca, Morelos, September 14. Guatemala--Tecpán, August 9.
Costa Rica--Vara Blanca, September 28.
_Banding._--A few interesting records of banded birds are available. One
banded at Hanover, N. H., on September 16, 1930, was found dead at
Milledgeville, Ga., on February 25, 1935. Since the bird was an adult
when banded it had lived at least five years and eight months. Another
banded at Groton, Mass., on May 24, 1933, was "caught" at West Memphis,
Ark., on October 22, 1933. A third bird, banded at Overbrook,
Philadelphia, Pa., was killed by an Indian near Tetela, Oaxaca, Mexico,
about April 1, 1936.
_Casual records._--A specimen of the black-throated green warbler was
collected on one of the Farallon Islands on May 29, 1911, and another
seen on June 1. There are three records for Arizona: one collected in
Ramsay Canyon, Huachuca Mountains, on May 9, 1895; one recorded seen in
the same mountains in August 1932; and one collected May 30, 1933, in
Toroweap Valley, Mohave County, on the brink of Grand Canyon. One was
noted on the Teton River below Collins, Mont., on June 4, 1916. A
specimen was collected at Barr Lake, Colo., May 20, 1909. In Monroe
Canyon, Sioux County, Nebr. one was noted October 8, 1920. At
Julianehaab, Greenland, a specimen was taken in 1853; and another at
Sukkertoppen in the fall of 1933. There are three records for Bermuda:
May 7, 1878; February 1927; and May 1, 1928. A specimen was secured on
the island of Heligoland, Germany, on November 19, 1858.