LYMNOTHLYPIS SWAINSONII (Audubon)
SWAINSON’S WARBLER
Contributed by Edward von Siebold Dingle
HABITS
“The history of our knowledge of Swainson’s Warbler,” write Brooks and Legg (1942), “is a curious one, falling into definite periods.” This bird was discovered in the spring of 1832 by the Rev. John Bachman “near the banks of the Edisto River, South Carolina.” His discovery of the bird is described as follows: “I was first attracted by the novelty of its notes, four or five in number, repeated at intervals of five or six minutes apart. These notes were loud, clear, and more like a whistle than a song. They resembled the sounds of some extraordinary ventriloquist in such a degree, that I supposed the bird much farther from me than it really was; for after some trouble caused by these fictitious notes, I perceived it near to me and soon shot it” (Audubon, 1841). Dr. Bachman took five specimens; then, up to the spring of 1884, Swainson’s warbler remained almost a lost species, for according to Brewster (1885a) there is no record of more than eight or nine birds being collected. Wayne, through collections and field work near Charleston, opened a productive 25-year period in the history of swainsonii, in which many valuable contributions were made by various observers. From 1910 to 1930 the name swainsonii was practically absent from the pages of current ornithological literature.
Brewster (1885a) has given us the best description of the bird’s haunts in the low country:
The particular kind of swamp to which he is most partial is known in local parlance as a “pine-land gall.” It is usually a depression in the otherwise level surface, down which winds a brook, in places flowing swiftly between well-defined banks, in others divided into several sluggish channels or spreading about in stagnant pools, margined by a dense growth of cane, and covered with lily leaves or other aquatic vegetation. Its course through the open pine-lands is sharply marked by a belt of hardwood trees nourished to grand proportions by the rich soil and abundant moisture. Beneath, crumbling logs cumber the ground, while an undergrowth of dogwood (Cornus florida), sassafras, viburnum, etc., is interlaced and made well-nigh impenetrable by a network of grapevines and greenbriar. These belts—river bottoms they are in miniature—rarely exceed a few rods in width; they may extend miles in a nearly straight line.
The writer has had a long acquaintance with Swainson’s warbler in the low country of Carolina. Except during September (fall migration) the birds were almost never seen out of sight of substantial growths of cane, even when the nests were built in bushes, low trees, or vines. This has been the experience of practically all observers and, as Brooks and Legg (1942) remark, “an idée fixe among ornithologists” existed; the familiar description of habitat by Brewster (1885a) became a dictum: “Briefly, four things seem indispensible to his existence, viz., water, tangled thickets, patches of cane, and a rank growth of semi-aquatic plants.”
Hence, the ornithological world received a surprise to learn that swainsonii was a summer resident and breeder in different localities of high altitude in the Appalachian Chain. Although several observers have found the bird nesting beyond the limits of the Coastal Plain, even in Piedmont territory, as La Prade (1922) did at 1,050 feet above sea level, it was E. A. Williams (1935) who first detected it in a truly mountainous terrain. During two successive summers he found birds near Tryon, N. C., “in open woods.”