This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Mr. Thos. Meehan remarked that Audubon, Nuttall, Wilson and other eminent ornithologists had suggested that the seasons had evidently not so much to do with the migrations of birds, as the question of food, though most authors connected this question of food with the autumn or winter season. He said he had recently observed the migration of the Robin (Turdus migratorius) in great numbers during the ten days prior to August 1st, or on the evenings of those days, for the flight was from about sundown to dark. They came from the north-west and were flying south east. Some were but a few hundred feet, but others were so high as to be scarcely visible, which would indicate a long journey. Robins had abounded on his property in Germantown during the past spring and early summer. He might say without exaggeration there were man)7 hundreds of them. On the day of this communication, August 1st, it was rare to meet with one. He considered the disappearance wholly one of food. On his grounds there had been no rain of any consequence for two months For two weeks past numerous trees and plants had to be kept alive by artificial waterings. Examining the dry earth after the harrow showed no signs of insect life. The cherry crop had been nearly a failure.
The usual berried plants, such as Dog-wood, on which they usually fed, were not ripe. There was really little for them to eat - and he had reason to believe that the same conditions prevailed all over northern Pennsylvania. In New Jersey, plants with berries were ripening, as they were also further south, and he concluded that this search for food was in this instance the cause of the early migration. - Proceedings of the Academy of Natural Sciences of Philadelphia.