seconds. The pitch varies from A´´´´ to D´´´´´, only three and a half
tones altogether. Single songs vary from one to two and a half tones in
range of pitch, averaging about one and a half tones. Individual birds
may sing as many as three different songs, and sometimes sing two
different songs in regular alternation.
"Singing continues from the first arrival in migration until the third
week of July, ceases for a short time, but is usually revived in August,
and is to be heard irregularly until the birds depart for the south."
Francis H. Allen gives me his impressions of the two common songs as
follows: "One of these I have been accustomed to render as _wee see wee
see wiss wiss´-u_. Occasionally the final _wiss´-u_ is doubled. The
other of these two songs goes something like _wee wee wee witita weet_,
without the drop in the pitch that the first song has at the final note.
I have also heard a song of five single notes with no variation in pitch
or tempo--_weet weet weet weet weet_. Besides a rather sharp _chip_,
which is the ordinary call-note, I have heard a _dzee_ from a yellow
warbler."
The yellow warbler is an early riser. Mr. Smith (1943) heard one begin
singing at 4:56 a.m., "daylight time," and another at 4:05, "but with
only one song until 4:08 when seven were given during the space of one
minute. During the song period of fifty minutes, 197 songs were given."
Dr. Charles W. Townsend told Mr. Allen that he heard one at Ipswich,
Mass., on June 13, 1908, that began singing at 3:10 a.m., but this was
standard time.
Dr. Winsor M. Tyler (1937) mentions a peculiar note, heard during the
migration in August, which had puzzled him for nearly 30 years until he
finally traced it to an eastern yellow warbler. "As we walk under the
trees, listening, we hear a long, wild, high, sharp bird-note, abrupt,
and very slightly vibratory, lasting perhaps half a second. It is a
characteristic sound of this time of year, and we hear it best on these
quiet, silent days. It comes from a bird moving restlessly up in the
trees, and before we can see the bird, it is gone. * * * In pitch, it
suggests the call of a migrating Ovenbird, but it is too long-drawn-out;
it suggests the _chip_ of a Northern Water-Thrush in its sharp
abruptness, but again it is too long."
According to Albert R. Brand (1938) there is considerable variation in
the pitch of the song of the eastern yellow warbler, from 8,775
vibrations per second in the highest note to 3,475 in the lowest note,
and with an approximate mean of 5,900 vibrations per second. This is far
below the approximate mean of 8,900 for the black-poll warbler, but well
above the average of 4,000 for all passerine birds.
_Field marks._--One hardly needs field marks to recognize a yellow
warbler; it is the yellowest of all our warblers at all seasons, even
the wing and tail feathers are edged with yellow, and there is no white
in either wings or tail. The youngest birds likewise show some yellow on
the under parts and in the flight feathers. See the descriptions of
plumages for details.
_Enemies._--The arch-enemy of the yellow warbler is undoubtedly the
cowbird. This warbler is one of the very commonest victims of this
parasite, and comparatively few of its nests are not visited at least
once by a cowbird in regions where the latter is very common. Dr.
Friedmann (1929) has about 500 records of such imposition on the eastern
yellow warbler. Everyone who has examined nests of this warbler in any
number has found one or more eggs of the cowbird in some of the nests.
This parasitic habit has cost this species of warbler many extra hours
of unexpected labor and the loss of many eggs and young. But the most
interesting fact about it is that the warbler has found a way to combat
the evil and, in many cases, to defeat the plans of the cowbird, by
either deserting the nest in which the strange egg is deposited or by
building a second floor over it and leaving the alien egg to cool off in
the "cellar."
The yellow warbler is not the only bird that has learned to do this
occasionally, but it is the only one that does it regularly and
persistently in spite of repeated contributions from the cowbird. Even
if the warbler has one of its own eggs in the nest when the cowbird's
egg is deposited it may bury both the eggs by building a story above
them, but if there are two or three warbler's eggs in the nest before
the alien egg appears, the warbler may feel obliged to incubate and
hatch out the stranger, with the usual results of her own young being
crowded out and lost. Two or more cowbird's eggs are almost sure to be
deserted or buried. But the cowbird is very persistent and keeps on
laying, as successive stories are added to the nest by the energetic and
persevering warblers. Two-story nests are very common, and as many as
three, four, five, and six stories have been recorded. Mr. Forbush
(1929) was told by Dr. H. F. Perkins "of one case where a six-storied
nest was built, with a cowbird's egg in every one." Mr. Du Bois tells me
of a new nest he found in a low bush, with another nest, about half
completed and only about a foot below it, containing a fresh, cold
cowbird's egg. Out of 43 nests found by Dr. George M. Sutton (1928) in
Pymatuning Swamp, Pa., "a Cowbird egg was found in only one nest. This
is most unusual, but is due, as elsewhere stated, to the protection
against these parasites afforded by the Red-winged Blackbirds which
would not tolerate a Cowbird anywhere about the marshes."
Snakes sometimes destroy the young, as related above; squirrels, blue
jays, and other predatory mammals and birds rob the nests; and the
adults must always be on the alert to escape the many enemies that prey
on all small birds.
Harold S. Peters (1936) records only one louse, _Philopterus
subflavescens_ (Geof.), as an external parasite on the eastern yellow
warbler.
_Fall._--The striking feature of the fall migration of the eastern
yellow warbler is its earliness. The birds begin to move away from their
nesting haunts as soon as the young are able to take care of themselves,
and the southward migration is well under way before midsummer. Smith
(1943) says that, in Vermont, "during many seasons, the species is not
seen later than July. Departure dates for local summer residents range
from July 15 to the 30th. Later records occur between August 18 and
September 9th." These later records are probably for birds from farther
north. There seems to be a wide spread between the times that the
earliest and latest birds leave.
Dr. L. H. Walkinshaw writes to me: "To me it is interesting how soon
after nesting has been completed these warblers disappear. After July
10, it is very hard to find one of the species here in Michigan, and
after August 10, almost impossible. It does stay some in certain good
feeding areas, but the majority have left long before August." According
to Milton B. Trautman (1940), the migration in Ohio begins early in
July, reaches its height during the first half of August, and only
stragglers are seen after September 10.
Arthur T. Wayne (1910) says that, in South Carolina--
the Yellow Warbler is positively uncommon during the spring migrations,
but exceedingly abundant in summer and autumn. * * * By July 4, the
return migration takes place and a few young birds arrive, but it is not
until the 10th or 15th that they are common. * * * The habits of the
birds are entirely changed, however, in summer and autumn, for then they
frequent the cotton fields, as well as lands which have been planted
with peas for forage. It is also not unusual in autumn to see as many as
twenty or more of these little birds far out in the salt marshes, where
they find food in abundance. The species is so very abundant in late
summer and autumn that it is not unusual to encounter hundreds of
individuals in a few hours on plantations or in close proximity to salt
water.
Prof. W. W. Cooke (1904) writes: "Though in migration the yellow warbler
occurs in Florida as far south as Key West and is sometimes fairly
common in northern Florida, the numbers that migrate through the
southern part of the State must be very small, for not a bird passing
north or south has been reported from any of the Florida lighthouses.
The migration route of the yellow warblers that breed near the Atlantic
coast is evidently southwest to northern Georgia and Alabama, and then
across the Gulf of Mexico."
Perhaps the main flight from Florida and the other Gulf States is across
the Gulf to Yucatán and then down through Central to South America, for
there seem to be no records for Cuba for the eastern yellow warbler.
There is a regular migration along the coast of Texas. Dickey and van
Rossem (1938) say that "the eastern yellow warbler migrates through El
Salvador in fair numbers, but no specimens were taken at any time during
the winter. In the fall, particularly, great numbers are in evidence.
The first arrivals reached Lake Olomega on August 1, but the main body
did not begin to drift through until about the middle of that month."
Frederick C. Lincoln (1939) remarks: "Redstarts and Yellow Warblers,
doubtless the more southern breeders in each case, have been seen
returning southward on the northern coast of South America just about
the time that the earliest of those breeding in the North have reached
Florida on their way to winter quarters."
_Winter._--Dr. Alexander F. Skutch contributes the following winter
notes: "This morning as I sat at breakfast a yellow warbler flitted
among the shrubbery outside the window. Here in Central America, through
8 or 9 months out of the 12, this well-known bird occupies the same
place in dooryard, garden, hedgerow and scrubby pasture as during its
briefer sojourn in the more northerly regions where it nests. None of
the resident warblers of Central America is quite so abundant and
familiar about human dwellings. Everywhere it avoids the heavy forest
and prefers the sunlight that floods the clearings made by man.
"It is one of the first of the visitants from the North to arrive in
Central America, appearing in Guatemala as early as August 9, reaching
Honduras by at least the fourteenth, Costa Rica by the seventeenth, and
Panamá by the twenty-second of the month. These early dates are for the
Caribbean lowlands, along which it appears to migrate. It arrives later
on the Pacific side of the Isthmus, especially in Costa Rica, where it
has not been recorded before August 24, at San José, and not until
September 11 in the Térraba Valley, still more isolated from the
Caribbean flyway by lofty, forested mountains. But by the end of
September, it is well distributed as a winter resident over both coasts
of Central America, and in the interior up to at least 5,000 feet,
becoming rarer at the upper limit of its altitudinal range. Much above
5,000 feet it apparently does not winter; but it is occasionally seen in
September in the high mountains as a bird of passage. A heat-loving
warbler, it is most common in the lowlands where, in the plantation
districts of northern Central America during the winter months, it is
among the most abundant birds, whether resident or migratory.
"Although a number of wood warblers which winter in the Central American
highlands are gregarious, those that center in the lowlands are
typically solitary. In this, the yellow warbler is no exception. Each
wintering bird appears to have its own territory, from which it attempts
to drive others of its kind. Trespassers are scolded with insistent
_chips_; or more rarely, soon after his arrival, a male will sing while
defending his claim. Near San Miguel de Desamparados, Costa Rica (4,600
feet), on October 1, 1935, I made the following note: 'This morning,
which for a change was bright and calm, I heard a yellow warbler singing
in the low fig trees near the house. Upon going out to look, I found
that there were two yellow warblers in the trees. One was trying to
drive the other away; but the pursued always circled around and
returned. I watched them for a long time; but this indecisive action
continued without any change in the situation. In the intervals of the
pursuit, the warblers (or at least one of them) would sing, but in a low
and imperfect fashion, far inferior to the yellow warbler's summer
song.' Again, on October 31: 'After the Wilson warbler, the most
abundant winter visitor is the yellow warbler. The bird who on October 1
drove its competitor out of the fig trees beside the house still retains
these trees and the surrounding _Inga_ trees as its domain.'
"The yellow warbler sings far less while in Central America than many
other wintering species. Exceptionally, one will be found singing
profusely. In early October, 1934, I came upon such a bird among the
coffee groves of a great plantation on the lower Pacific slope of
Guatemala. His behavior was so far out of the ordinary that I am tempted
to copy in full the notes I made upon it at the time: October 5--On the
afternoon of my arrival at 'Dolores,' I went out for a walk through the
coffee groves. From among the 'chalum' (_Inga_) trees which shaded the
coffee bushes, I heard a bird's song which seemed to belong to a
warbler; but I did not recognize it as the utterance of any species I
knew. After searching for a time among the tree-tops, I spotted the
singer, and was surprised to find him a yellow warbler. He was
apparently a young bird, for he lacked the chestnut splashes along the
sides which distinguish the mature males. He repeated over and over
again his little song of four or five notes, which was so unlike the
familiar song of the yellow warbler in the eastern United States that I
did not at first recognize it; but once I had identified the singer, I
realized that I was listening to a shortened and modified form of the
typical song.
"As I stood watching and listening to this eccentric warbler, the rain
clouds which had been gathering darkly in the west began to surrender
their pent-up waters; and the sudden shower approached across the
plantation with the roar of a myriad fat drops striking against the
large leaves of the Ingas and the far larger ones of the bananas which
shaded the plantation. I took refuge from the rain beneath the broad
expanse of a banana leaf, which completely shielded me from the beating
downpour. Soon the heavy shower exhausted itself; and I emerged from
beneath my green roof. The warbler, who had taken shelter from the
shower somewhere in the foliage above me, resumed his cheerful singing.
"'On the next two days, I passed by the spot where I had heard the
warbler singing, on the way to and from my botanical collecting ground.
Morning and afternoon, I heard the same voice in the same part of the
coffee plantation, where the bird seemed to have fixed his residence.'
"Yellow warblers may sing in Central America in the spring as well as
the fall. Last year, the male yellow warbler that wintered about my
house in Costa Rica sang briefly in the early morning from April 12 to
24. After April 28, I saw no more of his kind in the vicinity.
"From November 1936 until February of the following year, a yellow
warbler slept every night in a bush of _Hibiscus mutabilis_ beside my
cabin in Rivas, Costa Rica. He rested upon one of the long leaf-stalks,
where the broad blades of the higher leaves formed a roof above him, but
he was exposed on the sides and easily visible from the ground. He
always slept alone.
"Early dates of fall arrival in Central America are: Guatemala--passim
(Griscom), August 9; Sierra de Tecpán, 8,500 feet, September 4, 1933;
Huehuetenango, 6,500 feet, September 11, 1934. Honduras--Tela, August
14, 1930. Costa Rica--Puerto Limón, August 17, 1935; San José (Cherrie),
August 24; Cartago, September 6, 1938; Basin of El General, 2,000-3,000
feet, September 13, 1936 and September 11, 1942. Panamá--Canal Zone
(Arbib and Loetscher), August 22, 1934.
"Late dates of spring departure are: [British Guiana (Beebe), April 10.]
Panamá--Barro Colorado Island, April 23, 1935; Almirante, April 29,
1929. Costa Rica--Basin of El General, April 30, 1936, April 29, 1937,
May 7, 1939, May 3, 1940, April 28, 1942; San José (Cherrie), May 11.
Honduras--Tela, May 9, 1930. Guatemala--passim (Griscom), May 6; Los
Amates, Motagua Valley, May 11, 1932."
Todd and Carriker (1922), reporting for the Santa Marta region of
Colombia, say that the eastern yellow warbler is "a common winter
resident throughout the whole of the lowlands and lower foothills, but
rare above the coastal plain. It frequents shrubbery, open ground with
scattering bushes, the low growth along the banks of streams and the
sea-beach, etc.--the same kind of covert in general to which it is so
partial in the breeding season."
DISTRIBUTION
_Range._--North America, northern South America and the West Indies.
_Breeding range._--The yellow warblers of North America breed =north=
to north-central Alaska (Kobuk River and Fort Yukon); northern
Yukon (Potato Creek, 20 miles above Old Crow River); northwestern
Mackenzie (Richard Island, Fort Anderson, Lake St. Croix, and
Oot-sing-gree-ay-Island, Great Slave Lake); northern Manitoba (Lac Du
Brochet, Churchill, York Factory, and Severn House); and central Quebec
and Labrador (Richmond Gulf, Grand Falls of the Hamilton River, probably
Northwest River, and Cartwright). =East= to eastern Labrador
(Cartwright); Newfoundland (St. Anthony, Twillingate, and St. John's);
Nova Scotia (Cape Breton Island, Halifax, and Yarmouth); and the
Atlantic coastal region south to eastern and central North Carolina
(Pine Island, Lake Mattamuskeet, Raleigh, and Charlotte); central South
Carolina (Columbia); and central Georgia (Augusta and Macon). =South= to
central Georgia (Macon); central Alabama, rarely (Autaugaville);
southern Arkansas (Monticello and Arkadelphia); northeastern Texas
(Paris, Commerce, and Dallas); west-central Oklahoma (Fort Reno and
Thomas); southern New Mexico (Roswell and Silver City); probably
southwestern Texas (Fort Hancock and El Paso); northern Sonora
(Moctezuma, Magdalena, and Colonia Indepencia); and northwestern Baja
California (El Rosario). =West= to the Pacific coast from northern Baja
California (El Rosario) to western Alaska (Frosty Peak, Alaska
Peninsula; Nushagak, Hooper Bay, Saint Michael, and Kobuk River).
Wandering birds have been collected at Icy Cape and Wainwright on the
northwest coast of Alaska several hundred miles north of the
northernmost breeding record.
_Winter range._--The yellow warbler is found in winter =north= to
southern Baja California (La Paz); Jalisco (La Barca); Morelos
(Cuernavaca and Yautepec); southern Veracruz (Tlacotalpan); Yucatán
(Tunkás); and Quintana Roo (Akumal); occasional or accidental in winter
near Brownsville, Tex. =East= to Quintana Roo (Akumal); Honduras (Tela
and Ceiba); Nicaragua (Bluefields); Panamá (Almirante and the Canal
Zone); Venezuela (Trinidad Island); British Guiana (Georgetown and the
Berbice River); Surinam (Paramaribo); Cayenne (Cayenne and Approuague);
and northeastern Brazil (Chaves). =South= to northern Brazil (Chaves,
and Bôa Vista on the Rio Branco) and central Perú (La Merced). =West= to
central western Perú (La Merced); western Ecuador (Guayaquil, Chones,
and Esmeraldas); western Colombia (Condoto, Medellín, and Turbo);
western Costa Rica (El General, San José, and Bolson); El Salvador
(Puerto del Triunfo); western Guatemala (San José and Matzantinango);
Chiapas (Huehuetán); Guerrero (Coyuca); Colima (Manzanillo); and
southern Baja California (La Paz).
The range as outlined is divided into several subspecies or geographic
races. The Newfoundland warbler (_D. p. amnicola_) breeds from central
western Alaska south to central British Columbia, central Alberta,
Saskatchewan and Manitoba, central Ontario and Quebec northward and east
to Newfoundland; the Alaska yellow warbler (_D. p. rubiginosa_) breeds
in the coastal region of southern Alaska; the Rocky Mountain yellow
warbler (_D. p. morcomi_) breeds from southern British Columbia and
Washington east through the Rocky Mountains south to northern Nevada,
northern Utah and northern New Mexico; the California yellow warbler
(_D. p. brewsteri_) breeds west of the Sierras in Oregon and California;
the Sonora yellow warbler (_D. p. sonorana_) breeds from southeastern
California, southern Nevada, and southern New Mexico to northwestern
Mexico and western Texas; the eastern yellow warbler (_D. p. aestiva_)
breeds from southern Canada east of the Rocky Mountains southward. The
Cuban golden warbler (_D. p. gundlachi_) which is resident in Cuba, the
Isle of Pines, and adjacent Cays has been found nesting on Bay Key, Fla.
The mangrove, or "golden," yellow warbler (_D. p. castaneiceps_) breeds
on both coasts of Baja California from about latitude 27° 14´ N. (San
Lucas) southward; and on the west coast of Mexico from southern Sonora
(Guaymas) south to Nayarit (San Blas). (Apparently it is only slightly
migratory, if at all.)
_Migration._--Early dates of spring departure are: Perú--Iquitos, March
11. British Guiana--Abary River, March 25. Venezuela--Rancho Grande,
April 8. Colombia--Santa Marta Region, May 1. Panamá--Canal Zone, May
12. Costa Rica--San José, May 11. El Salvador--Chilata, April 24.
Guatemala--Quiriguá, May 11. Honduras--Tela, May 9. Mexico--Tabasco,
Balancán, May 11; Nuevo León, Montemorelos, May 21. Florida--Seven Oaks,
May 27. Mississippi--Deer Island, May 25. Louisiana--Chenier au Tigre,
May 21. Texas--Kerrville, May 31.
Early dates of spring arrival are: Florida--Pensacola, April 6.
Georgia, Athens, April 7. South Carolina--Charleston, April 3. North
Carolina--Windsor, April 4. Virginia--Lawrenceville, April 13. District
of Columbia--Washington, April 2. Pennsylvania--Wayne, April 4.
New York--New York, April 19. Massachusetts--Taunton, April 24.
Vermont--Burlington, April 28. Maine--Portland, May 2. New
Brunswick--Scotch Lake, May 1. Nova Scotia--Wolfville, May 8.
Quebec--East Sherbrooke, May 6. Prince Edward Island--North River, May
6. Newfoundland--St. Anthony, June 5. Louisiana--Avery Island, March 23.
Mississippi--Shell Mound, April 1. Arkansas--Tillar, April 5.
Kentucky--Eubank, April 12. Indiana--Richmond, April 14. Ohio--Oberlin,
April 12. Michigan--Ann Arbor, April 19. Ontario--London, April 20.
Missouri--St. Louis, April 15. Iowa--Cedar Rapids, April 20.
Wisconsin--Reedsburg--April 27. Minnesota--Minneapolis, April 27.
Texas--Victoria, March 28. Oklahoma--Stillwater, April 16.
Kansas--Topeka, April 16. Nebraska--Red Cloud, April 21.
South Dakota--Faulkton, April 22. Manitoba--Aweme, April 30.
Saskatchewan--Regina, May 4. Arizona--Fort Lowell, March 19.
New Mexico--Albuquerque, April 24. Utah--Provo, April 25.
Colorado--Littleton, April 23. Montana--Fortine, May 1.
Alberta--Camrose, May 3. Mackenzie--Simpson, May 21. California--Diablo,
March 12. Oregon--Portland, April 17. Washington--Camas, April 5.
British Columbia--Comox, April 25; Atlin, May 15.