Part 30

_Winter range._--The principal winter home of the black-throated blue warbler is in the West Indies where it is found =north= to the Bahamas (Andros, Nassau, and Watling Islands). =East= to Puerto Rico (Río Piedras) and the Virgin Islands (St. Croix). =South= to Puerto Rico (Maricas); Hispaniola (Paraíso, Dominican Republic; and Jérémie, Haiti); Jamaica (Spanishtown); and the Swan Islands. =West= to the Swan Islands; Cozumel Island; Cuba (Habana); and the Bahamas (Andros). It is also casual north to southern Florida (Sanibel Island, Key West, and Sombrero Key); accidental in Guatemala (Cobán); and in northern South America; Venezuela (Ocumare and Rancho Grande); and Colombia (Las Nubes, Santa Marta region, and Pueblo Viejo).

The species as outlined is divided into two subspecies or geographic races. The black-throated blue warbler (_D. c. caerulescens_) is found in Canada and in the United States south to Pennsylvania; Cairns' warbler (_D. c. cairnsi_) breeds in the Appalachian Mountains from southwestern Pennsylvania southward.

_Migration._--Late dates of departure from the winter home are: Puerto Rico--Consumo, April 3. Haiti--Morne à Cabrits, May 6. Cuba--Habana, May 11. Bahamas--Cay Lobos, May 14.

Early dates of spring arrival are: Florida--Fort Myers, March 4. Georgia--Fitzgerald, April 11. South Carolina--Spartanburg, April 5. North Carolina--Weaverville, April 19. Virginia--Lynchburg, April 21. District of Columbia--Washington, April 19. Pennsylvania--Swarthmore, April 25. New York--New York, April 28. Massachusetts--Amherst, May 2. New Hampshire--East Westmoreland, April 29. Maine--Auburn, May 3. Nova Scotia--Scotch Lake, May 7. Quebec--Quebec, May 7. Louisiana--New Orleans, March 22. Tennessee--Chattanooga, April 14. Kentucky--Lexington, April 24. Illinois--Urbana, April 26. Ohio--Canton, April 22. Michigan--Battle Creek, April 28. Ontario--Reaboro, May 3. Missouri--St. Louis, April 18. Iowa--Sigourney, April 21. Wisconsin--Ripon, April 28. Minnesota--Hibbing, May 8.

Late dates of the departure of transients in spring are: Florida--Daytona Beach, May 21. Georgia--Darien, May 20. South Carolina--Clemson (College), May 15. North Carolina--Raleigh, May 19. Virginia--Charlottesville, May 22. District of Columbia--Washington, May 30. Pennsylvania--Berwyn, June 3. Ohio--Ashtabula, May 29. Indiana--Fort Wayne, June 2. Michigan--Detroit, June 2. Illinois--Lake Forest, June 8. Wisconsin--Racine, June 4. Iowa--National, May 27.

Late dates of fall departure are: North Dakota--Fargo, October 21 (bird banded). Minnesota--Minneapolis, October 3. Wisconsin--Milwaukee, October 16. Iowa--Sigourney, October 20. Illinois--Chicago, October 25. Michigan--Grand Rapids, November 1. Indiana--Indianapolis, October 14. Ontario--Port Dover, October 27. Ohio--Medina, October 30. Kentucky--Eubank, October 22. Tennessee--Athens, October 18. Mississippi--Gulfport, October 12. Quebec--Montreal, October 15. New Brunswick--Saint John, October 11. Maine--Portland, October 17. New Hampshire--Water Village, October 8. Massachusetts--Cambridge, November 7. New York--Fire Island, October 24. Pennsylvania--Harrisburg, October 24. District of Columbia--Washington, October 29. Virginia--Lexington, October 15. North Carolina--Highlands, November 14. South Carolina--Clemson (College), October 17. Georgia--Athens, November 2. Florida--Fernandina, November 15.

Early dates of fall arrival are: Wisconsin--New London, August 23. Michigan--Grand Rapids, August 26. Ohio--Toledo, August 24. Illinois--La Grange, August 24. District of Columbia--Washington, August 21. Virginia--Charlottesville, September 12. North Carolina--Mount Mitchell, September 1. South Carolina--Mount Pleasant, August 30. Georgia--Savannah, August 28. Florida--Coconut Grove, August 29. Cuba--Cienfuegos, September 2. Dominican Republic--El Río, October 5. Puerto Rico--Las Marías, October 12.

_Casual records._--On the Farallon Islands, Calif., a specimen was found dead on November 17, 1886; it had been previously observed for three weeks. In New Mexico a specimen was taken at Gallinas Mountain on October 8, 1904, and on October 9, 1938 another was collected in Milk Ranch Canyon near Fort Wingate. In Bermuda a specimen was collected October 2, 1902; and it is considered a rare winter visitor. An individual spending the winter at a feeding stand in the suburbs of Washington, D. C., was observed closely from December 22, 1930, to January 16, 1931.

At sea the black-throated blue warbler has been observed on October 27, 1921, 12 hours run out from Port-au-Prince, Haiti, toward New York; and on March 29, 1918, in the Gulf of Mexico, 125 miles from Sabine Pass, La.

_Destruction at lighthouses._--Lighthouses with fixed white lights have caused considerable destruction of bird life during migration and the black-throated blue warbler seems to have been especially lured to those in southern Florida. Records were received from several of these lighthouses over a period of 5 or 6 years. Those from Sombrero Key are most detailed and give an interesting picture of migration at that point, since they include date, weather conditions, number of birds that struck, number killed, and hours during which the birds struck the light.

Comparatively fewer birds struck the light in spring than in fall. The spring dates are from March 9 to May 29; but in 4 years birds are reported to have struck the light only on 24 nights and 4 individuals is the greatest number reported.

In the fall, the records extend from September 3 to December 5, the heaviest nights being from the middle of September to late October. In two different years birds struck the light on 19 nights in two months. The greatest number in one night was 400 with 56 killed. In one of those years 1146 birds struck the light; of these 193 were killed. It was not only on stormy nights that the birds were attracted, as 130 struck and 15 were killed on a night described as calm and dark. Sometimes they kept striking all night, but on others the flight seems to have been concentrated, as when 300 birds struck in 3-1/2 hours. On a few occasions the mortality was as high as one-third of the birds that struck.

On the night of January 26, 1886, two birds struck the light. These were either wintering birds or extremely early migrants.

_Egg dates._--Massachusetts: 6 records, May 28 to July 5; 3 records, June 2 to 8.

New Hampshire: 17 records, June 3 to 22; 9 records, June 10 to 15.

New York: 51 records, May 29 to June 20; 37 records, June 3 to 12, indicating the height of the season.

Pennsylvania: 57 records, May 25 to June 26; 32 records, May 30 to June 6.

North Carolina: 10 records, May 5 to June 22; 6 records, June 4 to 11.

Virginia: 19 records, May 26 to June 18; 14 records, May 27 to June 4 (Harris).

DENDROICA CAERULESCENS CAIRNSI Coues

CAIRNS' WARBLER

PLATE 31

HABITS

This local race of the black-throated blue warbler, breeding in the southern Alleghenies, was named by Dr. Elliott Coues (1897) in honor of its discoverer and original describer, John S. Cairns of Weaverville, N.C. Dr. Coues, at that time, mentioned only the characters of the male, but those of the female are fully as well, perhaps more satisfactorily, marked than those of the male. Ridgway (1902) describes both very well and concisely as follows:

"Similar to _D. c. caerulescens_, but adult male darker above, especially the pileum, which is not lighter blue than the back, the latter usually more or less spotted or clouded with black, sometimes chiefly black, the pileum sometimes streaked with black; adult female darker and duller olive above and less yellowish beneath, with the olive of flanks darker and more strongly contrasted with the pale olive-yellowish of abdomen." In discussing its distribution, he was unable to define its breeding range with any degree of accuracy; and adds in a footnote: "On the whole, the form is not a very satisfactory one, one of the two characters on which it was based (smaller size) failing altogether (_D. c. cairnsi_ averaging slightly larger, in fact, than _D. c. caerulescens_), and the other only partially so, since many specimens of _D. c. cairnsi_ have little if any black on the back, while many of _D. c. caerulescens_ have quite as much as the average amount shown in _D. c. cairnsi_."

The 1931 A. O. U. Check-List gives the breeding range of _cairnsi_ as from Maryland to Georgia, but no definite line can be drawn; birds from southern Pennsylvania and Maryland, and perhaps the Virginias, are variably intermediate in their characters, and specimens can be found that are referable to either one or the other form.

Before this race had been separated from the northern form, Cairns (1896) wrote of its haunts:

High up on the heavily timbered mountain ranges of western North Carolina is the summer home of the Black-throated Blue Warbler.

Here in precipitous ravines, amid tangled vines and moss-covered logs, where the sun's rays never penetrate the rank vegetation and the air is always cool, dwells the happy little creature, filling the woods from dawn to twilight with its song. * * *

These birds are a local race; breeding from one generation to another. They arrive from the south nearly ten days earlier than those that pass through the valleys on their northward migration. It is common to observe migrants through the valleys while breeders on the higher mountains are already nest-building and rearing their young.

This statement agrees with Professor Cooke's (1904) later data, and with his statement: "The species is one of the few that appear in the mountains earlier than on the plains, and the case seems to sustain the theory that the individuals of a species that breed farthest south are the first to migrate in the spring."

_Nesting._--Cairns (1896) writes on this subject:

Nesting begins in May and continues until the end of June. The nests are placed in various shrubs, such as laurel, wild gooseberry, and chestnut, but the blue cohosh or papoose-root (_Caulophyllum thalictroides_) seems to be the favorite. These thick weeds grow rapidly to a height of from three to five feet, entirely hiding the ground, and thus afford the birds considerable protection. * * * The nests are never placed over three feet from the ground; usually about eighteen inches; one I examined was only six inches. * * *

The nests show little variation in their construction, though some are more substantially built than others. Exteriorly they are composed of rhododendron or grapevine bark, interwoven with birch-bark, moss, spider-webs, and occasionally bits of rotten wood. The interior is neatly lined with hair-like moss, resembling fine black roots, mixed with a few sprays of bright red moss, forming a strikingly beautiful contrast to the pearly eggs. The female gathers all the materials, and builds rapidly, usually completing a nest in from four to six days if the weather is favorable. She is usually accompanied by the male, which, however, does not assist her in any way.

Bruce P. Tyler of Johnson City, Tenn., has sent me some fine photographs (pl. 31) of the nests of this warbler, and says in his notes: "The Cairns warbler is found breeding in May, and later, on the southerly slope of Beech Mountain, just across the Tennessee line in North Carolina, at an elevation of 4,800 to 5,200 feet above sea level. The nest is built in small upright saplings or sprouts, 3 to 4 feet above the ground, and is constructed of shredded bark from the dying chestnut trees, rotten wood, etc., bound together with spiders' webs, and lined with fern rootlets and fine grass."

Thomas D. Burleigh (1927a) records four nests found, during May and June, on the slopes of Brasstown Bald in the northeastern part of Georgia: Two of these were in laurel bushes, 2 and 2-1/2 feet from the ground; another was 2 feet up in the fork of a small viburnum; and the fourth was 5 feet from the ground, "saddled near the end of a drooping limb of a rhododendron at the base of a large yellow birch well up the mountainside." A nest in my collection was taken by H. H. Bailey in Giles County, Va., at an elevation of 4,000 feet, on May 22, 1914; it was placed in a horsechestnut sprout alongside of a road, 1 foot above the ground. This and another nest before me are very similar to those described above.

_Eggs._--The 3 or 4 eggs laid by Cairn's warbler are practically indistinguishable from those of the black-throated blue warbler. The measurements of 30 eggs average 17.3 by 12.7 millimeters; the eggs showing the four extremes measure =19.0= by 13.0, 17.9 by =13.4=, and =16.0= by =12.0= millimeters (Harris).

DENDROICA CORONATA CORONATA (Linnaeus)

EASTERN MYRTLE WARBLER

PLATES 31-33

HABITS

We used to call this the yellow-rumped warbler, a none too distinctive name, as other warblers have yellow rumps. Another early and slightly better name, "yellow-crowned wood warbler," reflected the scientific name _coronata_ and was based on the old Edwards name "golden-crowned fly-catcher." The present name, Eastern myrtle warbler, comes from its fondness for the berries of the waxmyrtle (_Myrica cerifera_); and in the south, where it is common in winter, it is often called the myrtlebird.

Next to the yellow warbler, this is probably the best known of the wood warblers and is about the second one of the group that the novice learns to recognize. All through the eastern United States this is by far the most abundant warbler on both migrations, being about the first to arrive in the spring and the last to leave in the fall, often remaining all winter nearly up to the southern limits of its breeding range. It is a large, conspicuous warbler, not at all shy, and is to be found almost anywhere, often in enormous numbers. The breeding range of the species is one of the most extensive, extending from the tree limit in Alaska and northern Canada down through the coniferous forests into the northern tier of States, and even farther south in the mountains. Its winter range is still more extensive. It spends the winter farther north than any other wood warbler, although more or less sparingly and irregularly in the northern States, and its range extends through the Bahamas, the northern West Indies, Mexico, and Central America to Panamá. There is no wonder that it is well known. But neither Wilson, Audubon, nor Nuttall ever found its nest.

_Spring._--Professor Cooke (1904) writes:

The myrtle warbler is one of the first migrants to move northward. A large flight struck the Alligator Reef lighthouse February 23, 1892, and some 60 birds struck the Sombrero Key lighthouse March 3, 1889. By the middle of March migration is well under way over all the winter range, and the foremost birds keep close behind the disappearance of frost. * * * By the last of March all the myrtle warblers have departed from Jamaica, Haiti, Cuba, and the Bahamas. The latest recorded date of striking of this species at any of the Florida lighthouses is April 3, 1889. By the middle of the month the latest northbound birds have left southern Florida. * * * Most of the migrants cross the Rio Grande into Texas about the middle of March, and it is the middle of April before the last have passed north.

Charles L. Whittle (1922) witnessed a heavy migration of myrtle warblers along the coastal islands of South Carolina on March 4, 1920, that seemed to have been influenced largely by the presence of the waxmyrtle (_Myrica cerifera_). He says:

Perhaps half a mile from the northeast end of Sullivan Island the belt of waxmyrtle trees narrows to a width, measured northwest and southeast, of about three hundred feet. Here, near a seashore resort, a road had been recently cut across the belt of waxmyrtle trees at right angles to the sand bar. Streams of warblers flying along the shore northeasterly from Folly and Morris Islands, just south of the entrance to Charleston harbor, dropped to the land and converged at the southwest end of the mantle of myrtle trees and passed across the open swath cut for the new road. Posting ourselves here we counted the birds moving northeast, minute by minute as they passed the opening, for half an hour. The flight was continuous, many of the birds lighting on the ground and trees from time to time, and the number crossing per minute varied from twenty to two hundred, and accordingly averaged about one hundred per minute. As far as we could judge the number was no greater than it had been all the time since our arrival at the shore. Taking, therefore, the average at one hundred per minute, 24,000 Myrtle Warblers passed northward between nine in the morning and one in the afternoon. Not only so, but additional warblers passed close by both to the east and to the west of the stream of birds under observation. No doubt also the migration began prior to nine in the morning and did not cease at one in the afternoon.

He points out that the northern species of myrtle, or bayberry (_Myrica pensylvanica_), extends all along the coast from New Brunswick and Nova Scotia to Florida; and he suggests that if these warblers prefer to migrate along a coastal route where these myrtles reach their maximum development and where the climate may be milder than at higher elevations inland, it may explain why they generally arrive in New Brunswick a week earlier than in Pennsylvania.

Milton P. Skinner (1928) says that, in the North Carolina sandhills, "early in March the movement becomes conspicuous, and great numbers of these warblers are then seen constantly moving through the forests and across the fields in steady streams, flitting about a few minutes, and then passing on to the northeast. These movements are near the ground, or among the tree trunks, but at other times the birds are above the tallest trees. The general direction is from the southwest to the northeast, with fifty to a hundred warblers passing over a field each hour of every day for at least two weeks."

At Buckeye Lake, Ohio, according to Milton B. Trautman (1940)--

No warbler species migrated through the area in such consistently large numbers as did the Myrtle Warbler, and none had a more prolonged spring or fall migration. The first spring transients, mostly brilliant colored males, were generally seen between April 12 and 20. Thereafter the number of individuals increased rapidly, and from May 1 to May 5 between 100 and 200 birds, mostly males, could generally be daily noted. A marked decrease usually followed this migration wave. Between May 10 and 18, during the period of maximum numbers for most warbler species, there was a second large wave and then 150 to 500, mostly females and young males, were observed daily. A drastic decline in numbers took place shortly after May 18, and by May 23 few or none remained.

The migration is about the same in Massachusetts. The birds come in waves, the adult males preceding the females. We usually see the first arrivals about the middle of April, drifting through the leafless tree-tops in the tall deciduous woods where we look for hawks' nests; in their brilliant new plumage with gleaming yellow patches they are easily recognized as myrtle warblers, even in the tops of the 60-foot trees. Mr. Forbush (1929) gives this picture of the later waves:

In the latter days of April or very early in May when the south wind blows, when houstonias and violets begin to bloom on sunny southern slopes, when the wild cherry and apple trees and some of the birches, sumacs and the shrubbery in sheltered sunny nooks begin to put out a misty greenery of tiny leaflets, then we may look for the Myrtle Warblers, the males lovely in their nuptial dress of blue-gray, black, white and lemon-yellow. Then they may be found fluttering about in sheltered bushy bogs, catching the early insects that dance in the sunshine along the water-side. All through early May they move northward, or westward toward the mountains, migrating by day or night indifferently as the case may be.

Soon most of them have passed beyond our borders and reached their summer homes in the coniferous forests of the Canadian Zone, the first of the family to come, close on the heels of retreating winter and while frost and snow still linger in the northern woods.

_Courtship._--The courtship of the myrtle warbler must be a very pretty performance. Two brief accounts of it have been published: "As summer approaches the males begin their courtship of the females, following them about and displaying their beauties by fluffing out the feathers of their sides, raising their wings and erecting the feathers of the crown, so as to exhibit to the full their beautiful black and yellow markings. After much time spent in courting they mate, and at once look about for a nesting place" (Forbush, 1929). Males seeking mates "made advances to the female contingency, hopping from twig to twig with outspread wings, chipping and fluttering, now repulsed by the fair one, and now accepted by another one to whom advances were made, to finally spend a few days in a favorable spot and begin nest building" (Knight, 1908).

_Nesting._--On August 1, 1907, at Clarkes Harbor, Nova Scotia, I found the first and only nest of the myrtle warbler that I have ever seen; it was about 15 feet from the ground on a horizontal branch of a large spruce tree, about 5 feet out from the trunk, and contained three young birds that were nearly fully feathered. Robie W. Tufts says in his Nova Scotia notes: "I have seen these nests built at varying heights from 5 to 50 feet high. One found on June 6, 1919, contained four slightly incubated eggs. It was placed close to the stem of a pine tree, near the top, about 50 feet up. My field experiences tend to support the theory that these birds normally raise two broods a year." He found one nest built in an apple tree in an orchard, of which he says: "Of the large number of nests of this species I have examined, this is the only one not built in a conifer."

There are two Nova Scotia nests of the myrtle warbler in the Thayer collection in Cambridge, both taken by H. F. Tufts. They are slightly different in composition and structure, but are probably fairly typical of the species. One, found saddled on a spruce limb 10 feet from the ground, is rather bulky and loosely built; the foundation and sides are made of fine coniferous twigs mixed on the bottom with grasses and rootlets and around the rim firmly interwoven with black horsehair, or perhaps moose hair, and finer rootlets; the cup is smoothly lined with finer hair and feathers. Externally it measures, roughly, 4 by 5 inches in diameter and about 2 inches in height; the cup is about 2 inches in diameter and 1-3/4 inches deep. The other, a very pretty nest found 8 feet up in a small spruce, close to the trunk, is more firmly and compactly built; the base and sides are made up mainly of green mosses and a few gray lichens mixed with fine twigs and a few fine grasses, all firmly interwoven; internally the cup is smoothly lined with fine black and white hairs on top of a few feathers. Externally it measures 2-1/4 inches in height and 3 by 3-1/2 inches in diameter; the cup is 2 inches in diameter and about 1-1/2 inches deep.

Of nestings in Maine, Knight (1908) says: "As soon as nest building begins, the favorite locality selected is a thicket of evergreen trees near the highway, some open pasture containing a few clumps of scattered evergreens, small thickets of evergreens along the banks of some stream or river or about the shore of a pond or lake, or a row of trees about some country dwelling or in an orchard. In the vast majority of cases an evergreen tree is selected as a nesting site, though occasionally some hardwood tree, such as maple, apple or birch, may be taken. A majority of nests seem to be placed in cedar trees, with fir and spruce following as close second choices."