at midnight with a full moon:
Interesting Facts: A group of warblers has many collective nouns, including a "bouquet", "confusion", "fall", and "wrench" of warblers.
As in other migratory species, the males precede the females several days. As soon as they have arrived, they give free vent to their song at all hours of the day, renewing it at night when the weather is calm, and the moon shines brightly, seeming intent on attracting the females, by repeating in many varied tones the ardency of their passion. Sometimes the sounds are scarcely louder than a whisper, now they acquire strength, deep guttural notes roll in slow succession as if produced by the emotion of surprise, then others clear and sprightly glide after each other, until suddenly, as if the bird had become confused, the voice becomes a hollow bass. The performer all the while looks as if he were in the humour of scolding, and moves from twig to twig among the thickets with so much activity and in so many directions, that the notes reach the ear as it were from opposite places at the same moment. Now the bird mounts in the air in various attitudes, with its legs and feet hanging, while it continues its song and jerks its body with great vehemence, performing the strangest and most whimsical gesticulations; the next moment it returns to the bush. If you imitate its song, it follows your steps with caution, and responds to each of your calls, now and then peeping at you for a moment, the next quite out of sight. Should you have a dog, which will enter its briary retreat, it will skip about him, scold him, and frequently perch, or rise on wing above the thicket, so that you may easily shoot it.
The arrival of the females is marked by the redoubled exertions of the males, who now sing as if delirious with the pleasurable sensations they experience. Before ten days have elapsed, the pairs begin to construct their nest, which is placed in any sort of bush or briar, seldom more than six feet from the ground, and frequently not above two or three. It is large, and composed externally of dry leaves, small sticks, strips of vine bark and grasses, the interior being formed of fibrous roots and horse-hair. The eggs are four or five, of a light flesh colour, spotted with reddish-brown. In Louisiana and the Carolinas, these birds have two broods in the season; but in Pennsylvania, where they seldom lay before the 20th of May, they have only one brood. The eggs are hatched in twelve days. The male is seldom heard to sing after the breeding season, and they all depart from the Union by the middle of September.