Part 56

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.