Part 43

A partial postjuvenal molt begins early in August, involving the contour plumage and the wing coverts but not the rest of the wings or the tail. This produces the first winter plumage, which he describes as "above, deep yellowish olive-gray, flecked on the crown and streaked on the back with black; obscure median crown stripe straw-yellow; rump and upper tail coverts black, edged with olive-gray. Wing coverts clove-brown edged with olive-gray and tipped with white forming two broad wing bands. Below, straw-yellow brightening to orange-tinged lemon on the throat, fading to buffy white on the crissum and narrowly streaked on the sides with black veiled by yellow edgings. Superciliary stripe and post-auricular region lemon-yellow orange-tinged. Auriculars, rictal streak and transocular stripe olive-gray mixed with black. Suborbital spot yellowish white."

He says that the first nuptial plumage is "acquired by a partial prenuptial moult which involves most of the body plumage (except posteriorly), the wing coverts and sometimes the tertiaries but not the rest of the wings nor the tail. The full orange and black plumage is assumed, young and old becoming practically indistinguishable, the orange throat equally intense in both, the wings and tail usually browner in the young bird and the primary coverts a key to age."

The adult winter plumage is acquired by a complete postnuptial molt in July, and "differs little from the first winter dress, but the yellow more distinctly orange, the transocular and rictal streaks, the crown and auriculars distinctly black, veiled with orange tips, the streaking below heavier and broader, the wings and tail blacker and the edgings grayer." The adult nuptial plumage is acquired as in the young bird; this molt evidently begins in February, while the birds are in their winter quarters, and is usually finished before they reach their summer homes.

Of the females, Dr. Dwight says:

The plumages and moults correspond to those of the male. In juvenal plumage the wing edgings are usually duller, the first winter plumage being similar to that of the male but browner, the yellow tints nearly lost and the streakings obscure and grayish. The first nuptial plumage, assumed by a more or less limited prenuptial moult, is grayer above and paler below, except on the chin and throat where new pale orange feathers contrast with the worn and faded ones of the breast. The adult winter plumage is practically the same as the male first winter, the auriculars and transocular stripe usually duller. The adult nuptial plumage is brighter below than the first nuptial and with more spotting on the crown, but the black head and bright orange throat of the male are never acquired.

_Food._--The Blackburnian warbler is mainly insectivorous like other wood warblers, feeding almost entirely on the forest pests that are so injurious to the trees. F. H. King (1883), writing of its food in Wisconsin, says: "Of nine specimens examined, four had eaten nine small beetles; five, nineteen caterpillars; one, ants; and one, small winged insect. In the stomachs of three examined collectively, were found four caterpillars, four ants, one dipterous insect .09 of an inch long, one medium sized heteropterous insect, four large crane-flies, and one ichneumon-fly (?). Another bird had in its stomach one heteropterous insect (_Tingis_), nine small caterpillars, two leaf-beetles, and two large crane-flies."

Ora W. Knight (1908) writes: "In general I have found large quantities of the wing cases and harder body portions of beetles in the stomachs of such Blackburnian Warblers as I have dissected, also unidentifiable grubs, worms, larvae of various lepidopterous insects and similar material. As a rule they feed by passing from limb to limb and examining the foliage and limbs of trees, more seldom catching anything in the air."

R. W. Sheppard (1939), of Niagara Falls, Ontario, observed a male Blackburnian warbler in his garden for several days, November 5 to 11, 1938, that appeared to be traveling with two chickadees, among some willow trees. "An examination of the row of low willow trees which appeared to be so attractive to this particular warbler, revealed the presence of numbers of active aphids and innumerable newly laid aphis eggs, and it is probable that these insects and their eggs provided the major incentive for the repeated and prolonged visits of this very late migrant."

Henry D. Minot (1877) observed "a pair feeding upon ivy berries" on April 21, when insects were not yet common in Massachusetts.

_Behavior._--William Brewster (1938) describes what he thought was the unique behavior of a female Blackburnian warbler at its nest, although a similar habit has been observed in other wood warblers. Even though the eggs "were perfectly fresh the female sat so closely that thumping and shaking the tree (a slender one) failed to start her, and when Watrous climbed it he nearly touched her before she slipped off. She then dropped like a stone to the ground over which she crawled and tumbled and fluttered with widespread tail and quivering wings much like a Water Thrush or Oven Bird and evidently with the hope of leading us away from the nest."

The Blackburnian is pre-eminently a forest warbler and a tree-top bird. On migrations it frequents the tops of the trees in the deciduous forests, often in company with other wood warblers; and on its breeding grounds in the coniferous forests the male loves to perch on the topmost tip of some tall spruce and sing for long periods, his fiery breast gleaming in the sunlight. As his mate is probably sitting on her nest not far away, his serenity may be disturbed by the appearance of a rival; but the intruder in his territory is promptly driven away and he resumes his singing.

_Voice._--Aretas A. Saunders has sent me the following study: "The song of the Blackburnian warbler is one that is usually of two distinct parts, the first a series of notes or 2-note phrases all on one pitch, and the second a faster series, or a trill, on a different pitch. It is very high in pitch, with a thin, wiry quality, rather unmusical, and not loud but penetrating.

"Of my 34 records, 25 have the second part higher in pitch than the first, while in the other 9 it is lower. I do not think, however, that this means that the higher ending is commoner, for there is reason to think that the difference is geographical. Of 11 records of migrating birds in Connecticut, 10 end in the higher pitch. Of 15 records from breeding birds in the Adirondacks, 13 end in the higher pitch; but of 8 records of breeding birds in Allegany State Park in western New York, only 2 end in the higher pitch, and 6 in the lower.

"In 20 of the records the first part of the song is of 2-note phrases, but the remainder is of single repeated notes. In 6 records, ending in a higher pitch, the final trill slurs upward in pitch, suggesting the ending of a typical parula song in form. In 10 of the records the second part is much shorter than the first.

"Songs vary from 1-2/5 to 2-2/5 seconds, averaging a little longer than those of other species of this genus. The number of notes in songs, excepting those with trills, varies from 7 to 25, and averages 14. Pitch varies from D´´´´ to F´´´´, one and a half tones more than an octave. It ranks with the black-polled and bay-breasted warblers in the very high pitch of its upper notes but shows more variation in pitch than either.

"The song of this bird ceases earlier in summer than most others. In 14 summers in Allegany Park, the average date of the last song was July 12, the earliest July 4, 1929, and the latest July 22, 1935. I have never heard singing in late summer after the molt."

Francis H. Allen sends me his impressions as follows: "Like so many of our warblers, the Blackburnian has two song-forms, but both are subject to great individual variation. An extremely high note is almost an invariable characteristic. In one form it is the closing note, and in the other it ends each repeated phrase of a succession that constitutes the main part of the song. The first song resembles that of the parula, but ends with this high note, while the main part is less buzzy and more what I might call pebbly in character. The second I have been accustomed to call the chickawee song because of the repeated phrase which suggests those syllables. At Sherburne, Vt., in June, 1907, I found the Blackburnians singing a song that I rendered as _ch[)i]-ee ch[)i]-ee ch[)i]-ee ch[)i]-ee chip_. Another rendering of the same or a similar song, recorded at Jaffrey, N. H., May 30, 1910, was _serwée serwée serwée serwée serwíp_, with the emphasis on the _wip_. At New London, N. H., in June, 1931, where this was perhaps the commonest of the warblers, I was particularly impressed by the variability of both the songs. In some, the very high and attenuated notes were so short that for some time I failed to recognize their source. One bird sang _chiddle chiddle chiddle chick-a chick-a cheet_. At Hog Island in Muscongus Bay, Maine, in June, 1936, I heard a song of which only a sweet _weet weet weet weet_ carried to a distance, but of which, heard near at hand, the end was found to be a short, confused succession of high-pitched, dry notes concluding with a very high, short note. This was, I think, the most pleasing performance I have ever heard from this species."

Mrs. Nice (1932) mentions three different songs; the commonest and shortest, like the parula's in form, lasts for one second and is given at intervals of 7-1/2 to 10 seconds; the rarest and longest lasts for two seconds and is given at intervals of 10 or 14 seconds.

A. D. DuBois tells me that the Blackburnian warbler "has a song not unlike that of the dickcissel in its general form, although much subdued in volume." Gerald Thayer wrote to Dr. Chapman (1907) of two or more different songs of this warbler, and says:

Its voice is thin, but, unlike the Parula's, exquisitely smooth, in all the many variations of its two (or more) main songs. * * * Even the tone quality is not quite constant, for though it never, in my experience, varies toward huskiness, it does occasionally range toward full-voiced richness. Thus I have heard a Blackburnian that began his otherwise normal song with two or three clear notes much like those of the most full and smooth-voiced performance of the American Redstart's, and another that began so much like a Nashville that I had to hear him several times, near by, to be convinced that there was not a Nashville chiming in. Sometimes, again, tone and delivery are varied toward excessive languidness; and sometimes, contrariwise, toward sharp, wiry "thinness."

_Enemies._--Dr. Friedmann (1929) calls the Blackburnian warbler "a very uncommon victim of the Cowbird." Dr. Merriam (1885) records a nest of this warbler that was 84 feet from the ground, containing four warbler's eggs and one of the cowbird, of which Friedmann remarks: "This is probably the altitude record for a Cowbird's egg, bettering by some twenty feet my highest record at Ithaca, a Cowbird's egg in a nest of a Pine Warbler about sixty feet up."

Harold S. Peters (1936) records two species of lice, _Menacanthus chrysophaeum_ (Kellogg) and _Ricinus_ pallens (Kellogg), and one mite, _Proctophyllodes_ sp., as external parasites of this warbler.

_Field marks._--The adult male Blackburnian warbler in spring plumage is unmistakable, with its black upper parts, large white patch in the wings, orange stripe in center of the crown and another over the eye, and, especially, the flaming orange throat and breast. The female in the spring and the male in the fall are similarly marked, but the colors are much duller. The colors of young birds in the fall are even duller, and the back is brownish, but the white outer web of the basal half of the outer tail feather should indicate the species.

_Fall._--Early in August, young and old birds begin to gather into flocks preparing to migrate, and before the end of that month most of them have left their breeding grounds. All through August and most of September, we may see them drifting through our deciduous woods in mixed flocks with other species of warblers. These migrating flocks are generally so high up in the tree tops and are so active in their movements that it is not easy to identify them in their dull winter plumages.

By early October, most of the Blackburnian warblers have passed beyond the United States, en route to their winter home in South America. Professor Cooke (1904) says: "By the middle of October the earliest migrants have reached Venezuela and Ecuador. The main army of the Blackburnians pass the south end of the Alleghenies between September 25 and October 5, and during the first two weeks of October are moving through San José, Costa Rica, and by early in November are settled for the winter in Perú."

Dickey and van Rossem (1838) refer to it as a "fairly common fall migrant and very rare winter visitant in the Arid Lower Tropical Zone" in El Salvador, but "not seen in spring."

_Winter._--Dr. Alexander F. Skutch contributes the following notes: "Rarely recorded, and apparently only as a bird of passage, in Guatemala, the Blackburnian warbler is a moderately abundant winter resident in Costa Rica. Here it passes the winter months on both slopes of the Cordillera, from about 1,500 to 6,000 feet above sea-level, but is far more abundant above than below 3,000 feet. It is found in midwinter both in heavy forest and among scattered tall trees. Although the birds appear to arrive in flocks in late August or September, they soon disperse through the woodland and show slight sociability. Yet one or two may at times join a mixed flock of Tennessee warblers and other small birds. Restlessly active, the Blackburnian warbler forages well above the ground, where it is difficult to see. I have never heard its song in Central America.

"Early dates of fall arrival are: Guatemala--Chimoxan (Griscom), October 1; Panajachel (Griscom), October 4. Costa Rica--San José (Cherrie), September 8; San José (Underwood), Septem 10; La Hondura (Carriker), September 19; San Isidro de Coronado, September 8, 1935; Vara Blanca, August 19, 1937; Cartago, September 13, 1938; Murcia, September 14, 1941; Basin of El General, September 16, 1936; Ujarrás (Carriker), September 12. Ecuador--Volcán Tungurahua, 7,400 feet, October 12, 1939.

"Late dates of spring departure from Central America are: Costa Rica--Basin of El General, March 25, 1936, March 13, 1937 and April 18, 1943; Vara Blanca, May 7, 1938; Pejivalle, April 23, 1941; Bonilla (Basulto), April 10. Guatemala--Finca Sepacuite (Griscom), May 10."

DISTRIBUTION

_Range._--Southern Canada east of the Great Plains to Central Perú.

_Breeding range._--The Blackburnian warbler breeds =north= to southern Manitoba (Lake St. Martin and Berens Island, Lake Winnipeg); central Ontario (Lac Seul, Lake Abitibi, and North Bay; has occurred at Trout Lake); and central Quebec (Blue Sea Lake, Lake Albanel, rarely; Lake St. John and Gaspé; possibly Pointe de Monts and Natashquan). =East= to eastern Quebec (Gaspé); eastern New Brunswick (Bathurst and Tabusintac); and eastern Nova Scotia (Antigonish and Halifax). =South= to Nova Scotia (Halifax); southern Maine (Calais, Lewiston, and Portland); Massachusetts (Cambridge, Springfield, and Sheffield); northern New Jersey (Kittatinny Mountains); central Pennsylvania (Mauch Chunk and Carlisle); and south through the mountains of Maryland, Virginia, West Virginia, North and South Carolina and Tennessee to northern Georgia (Brasstown Bald and Burnt Mountain); western Pennsylvania (Leasureville and Meadville); northeastern Ohio (Pymatuning Swamp and possibly Geneva); northern Michigan (Bay City and Wequetonsing); northern Wisconsin (New London, Unity and Ladysmith); and northern Minnesota (Elk River, Onamia, and Itasca Park). =West= to northwestern Minnesota (Itasca Park) and southeastern Manitoba (Winnipeg and Lake St. Martin).

A possible future extension of range westward is seen in records from Saskatchewan: it was recorded four times near Indian Head 1888-1901; one at Last Mountain Lake in 1920, at Lake Johnston in 1922; and at Emma Lake in the summer of 1939, possibly breeding.

_Winter range._--The Blackburnian warbler is reported to winter commonly in Costa Rica, but as yet has been found in Panamá only as a migrant. In South America it is found =north= to northern Colombia (Santa Marta region); and central northern Venezuela (Rancho Grande). =East= to northwestern Venezuela (Rancho Grande, Mérida, and Páramo de Tamá); the eastern slope of the Andes in Colombia (Pamplona, Bogotá, and San Antonio); Ecuador (Mount Sumaca, Machay, and Zamora); and Perú (Chinchao and Huambo). =South= to central Perú (Huambo and Anquimarca). =West= to western Perú (Anquimarca and Tambillo); Ecuador (Ambato, Quito, and Parambo); and Colombia (Concordia, Medellín, and the Santa Marta region). It is casual in migration in the Bahamas and Cuba.

_Migration._--Late dates of spring departure from the winter home are: Perú--Chelpes, April 22. Ecuador--Quito, May 10. Venezuela--Rancho Grande, April 22. Colombia--La Porquera, April 24. Costa Rica--Vera Blanca, May 7.

Early dates of spring arrival are: Panamá--Garachiné, March 5. Florida--Pensacola, April 5. Alabama--Hollins, April 4. Georgia--Athens, March 29. South Carolina--Aiken, April 17. North Carolina--Weaverville, April 16. Virginia--Lynchburg, April 25. West Virginia--White Sulphur Springs, April 17. District of Columbia--Washington, April 23. Pennsylvania--Renovo, April 27. New York--Rochester, April 26. Massachusetts--Melrose, April 29. Vermont--Wells River, April 30. Maine--Portland, May 4. New Brunswick--Scotch Lake, May 5. Quebec--Montreal, May 10. Louisiana--Lake Borgne, March 27. Mississippi--Gulfport, March 27. Tennessee--Chattanooga, March 31. Kentucky--Lexington, April 12. Indiana--Brookville, April 15. Ohio--Oberlin, April 19. Michigan--Hillsdale, April 22. Ontario--London, April 27. Arkansas--Huttig, April 15. Missouri--Bolivar, April 20. Iowa--Davenport, April 28. Wisconsin--Unity, April 27. Minnesota--Waseca, April 30. Texas--Boerne, March 31. Nebraska--Stapleton, May 1. South Dakota--Vermilion, May 3. Manitoba--Aweme, May 14.

Late dates of spring departure of transients are: Florida--Pensacola, May 9. Alabama--Autaugaville, May 12. Georgia--Athens, May 7. South Carolina--Spartanburg, May 12. North Carolina--Greensboro, May 17. Virginia--Charlottesville, May 28. District of Columbia--Washington, June 3. Pennsylvania--Norristown, May 30. New York--New York, June 7. Louisiana--New Orleans, April 23. Mississippi--Corinth, May 12. Kentucky--Lexington, May 16. Illinois--Lake Forest, June 9. Ohio--Toledo, June 12. Arkansas--Rogers, May 12. Missouri--Kansas City, May 30. Iowa--Sigourney, June 1. Texas--Commerce, May 18. Nebraska--Fairbury, May 26. South Dakota--Yankton, June 2.

Late dates of fall departure are: Saskatchewan--Last Mountain Lake, September 1. Nebraska--Fairbury, October 14. Texas--Brownsville, October 2. Minnesota--Saint Paul, September 25. Wisconsin--Madison, September 27. Ontario--Hamilton, October 3. Michigan--Ann Arbor, October 8. Indiana--Waterloo, October 17. Kentucky--Danville, October 16. Missouri--St. Louis, October 6. Tennessee--Memphis, October 28. Arkansas--Chicat, October 4. Mississippi--Eudora, October 24. Louisiana--New Orleans, October 9. Quebec--Hatley, September 30. New Brunswick--Scotch Lake, September 28. Maine--Phillips, September 17. New Hampshire--Hanover, September 24. Massachusetts--Wellesley, October 23. New York--Canandaigua, October 12. Pennsylvania--Berwyn, October 19. District of Columbia--Washington, October 10. West Virginia--Bluefield, October 8. Virginia--Sweet Briar, November 1. Georgia--Tifton, November 2. Alabama--Birmingham, October 25. Florida--Arcadia, October 30. Cuba--Bosque de la Habana, October 30.

Early dates of fall arrival are: North Dakota--Argusville, August 23. Texas--Commerce, August 28. Illinois--Glen Ellyn, August 19. Ohio--Little Cedar Point, July 31. Kentucky--Versailles, August 31. Tennessee--Nashville, August 29. Mississippi--Bay St. Louis, August 11. New York--New York, August 11. Pennsylvania--Berwyn, August 19. District of Columbia--Washington, August 2. Virginia--Charlottesville, August 10. North Carolina--Mount Mitchell, July 30. Georgia--Savannah, August 10. Florida--Key West, July 29. Cuba--Santiago de las Vegas, September 20. Costa Rica--San José, August 17. Colombia--Santa Isabel, September 22. Venezuela--Escorial, October 14. Ecuador--Tumbaco, October 12. Perú--Tambillo, November 19.

_Casual records._--A specimen of Blackburnian warbler was collected at Frederickshaab, Greenland, on October 16, 1845. One was taken at Ogden, Utah, in September 1871, and another near Fort Bayard, N.M., in May 1876. On August 21, 1924, a male was watched closely for sometime near Libby, Mont.

_Egg dates._--Maine: 5 records, June 2 to 17.

New York: 23 records, May 29 to July 6; 16 records, June 7 to 17, indicating the height of the season.

New Hampshire: 6 records, May 23 to June 18.

Pennsylvania: 5 records, May 28 to June 9.

Quebec: 2 records, June 15 and 20.

DENDROICA DOMINICA DOMINICA (Linnaeus)

EASTERN YELLOW-THROATED WARBLER

CONTRIBUTED BY ALEXANDER SPRUNT, JR.

PLATES 42, 43

HABITS

One of the botanical attractions of the South is the Spanish moss (_Tillandsia usneoides_) that drapes with its graceful, swaying strands the cypresses in the lagoons and backwaters, the live oaks that stand in spectacular avenues on the approaches of so many plantations of the Carolina Low Country and in magnificent groves throughout the Coastal Plain, and even the pines that forest wide reaches of Georgia and northern Florida. To many ornithologists the thought of this Spanish moss brings to mind the birds partial to it, particularly the eastern yellow-throated warbler. Indeed, in the coastal part of the range of this bird the two are all but synonymous, so that where the moss is scarce, so, too, is the eastern yellow-throated warbler. Since childhood I have thought of this little gray and yellow sprite, one of the handsomest of a handsome tribe, as the animated spirit of the Spanish-moss country.

_Spring._--The eastern yellow-throated warbler is much less migratory than many species of its genus. In the southern portion of its range it is a permanent resident, though of course, quiet at that season and therefore difficult to find; but it occurs throughout the year and can be seen on almost any day in winter from the Charleston, S. C., area southward to Lake Okeechobee, Fla.

In Florida, though it is resident in much of the state, a marked increase of migrants from the south occurs in late February and early March. Arthur H. Howell (1932) states that "the beginning of spring migration is indicated by the appearance of the birds at Sombrero Key Light March 11th." He also states that F. M. Chapman noted arrivals at Gainesville on March 2. (Some birds are mated by March 11 in the vicinity of Charleston.) Thus, the spring migration seems a rather erratic and long-drawn-out movement.

In the Pensacola region of Florida, F. M. Weston (MS.) writes: "Birds that have wintered commence singing, and thus become conspicuous, early in March. Incoming migrants gradually add to the number until, by the first of April, the species is common and widely distributed in all areas where Spanish moss is present. Howell considers this species as one of the typical birds of the pine forests, but in this region, where the moss is never found in pure stands of pine, the bird is absent from the pine woods. In the Dead Lakes area, south of Marianna, Fla., a drowned cypress swamp, the cypresses are covered with dense masses of moss and the yellow-throated warbler is one of the characteristic birds."