_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.