None of our birds, before its history was well known, has been made the occasion for more ill-founded conjectures than the Black-Poll. Wilson was at fault as to its song and its Southern breeding, and imagined it would be found to nest in high tree-tops, so as not to be readily detected. Nuttall, on the other hand, predicted that it would be found to breed on the ground, after the manner of the _Mniotiltae_, or else in hollow trees. Mr. Audubon, finding its nest in Labrador, indulges in flights of fancy over its supposed rarity, which, seen in the light of our present knowledge, as an abundant bird in the locality where his expedition was fitted out, are somewhat amusing. That nest was in a thicket of low trees, contained four eggs, and was placed about four feet from the ground, in the fork of a small branch, close to the main stem of a fir-tree. Its internal diameter was two inches, and its depth one and a half. It was formed, externally, of green and white moss and lichens, intermingled with coarse dry grasses. It was lined, with great care, with fine, dry, dark-colored mosses, resembling horse-hair, with a thick bed of soft feathers of ducks and willow grouse. In passing north, these Warblers, says Audubon, reach Louisiana early in February, where they glean their food among the upper branches of the trees overhanging the water. He never met with them in maritime parts of the South, yet they are abundant in the State of New Jersey near the sea-shore. As they pass northward their habits seem to undergo a change, and to partake more of the nature of Creepers. They move along the trunks and lower limbs, searching in their chinks for larvæ and pupæ. Later in the season, in more northern localities, we again find them expert flycatchers, darting after insects in all directions, chasing them while on the wing, and making the clicking sound of the true Flycatcher. They usually reach Massachusetts after the middle of May, and their stay varies from one, usually, to nearly four weeks, especially when their insect-food is abundant. In our orchards they feed eagerly upon the canker-worm, which is just appearing as they pass through.