Swamp Sparrows are common, and their clear trill is one of the few August songs. Bobolinks, traveling in disguise and under the assumed name of “Reedbird,” pause here to feed on the ripening wild rice.[47] Some of them have not yet completed their change of costume and appear in a spotted suit of black and yellow. Occasionally one hears a suppressed burst of the “mad music” of June, but their common note is a metallic chink. At night this note is heard from high in the air, as the birds continue their journey to the cultivated rice fields of South Carolina and Georgia, there to remain until September or October, when they leave for their winter home south of the Amazon.
The Sora Rails, beloved of sportsmen and epicures, are also attracted to the marshes by the wild rice. On their arrival in early August they are indeed “as thin as a rail,” but an abundance of food soon rounds their bodies into comparative plumpness. The 1st of September is a black day in their calendar. Then they are outlawed, a price is set on their bodies, and at high tide each day during this sad month one sees numerous puffs of smoke arise from the tall grasses and dull reports come booming over the marsh with fateful frequency.
But the characteristic birds of the marshes at this season are Swallows. They outnumber many times all the rest of the marsh birds together—in fact, are present in such myriads that their gatherings are one of the most interesting and impressive phenomena of the bird life of this region.
Five species are represented. Named in the order of their abundance they are the Tree, Bank, Barn, Eave, and Rough-winged Swallows. The last are comparatively rare, while the Tree Swallows are so in excess of all the species named that the following remarks relate largely to them alone.
Although Tree or White-breasted Swallows nest locally throughout North America, from the tableland of Mexico to Labrador and Alaska, there are but few instances of their breeding in the lower Hudson River valley, where they appear only as migrants or transient visitants. They arrive from the south early in April, and their northward migration is not concluded until about June 1st. During June they are rarely seen, but between the 1st and the 5th of July they begin their journey to their winter homes—a movement which inaugurates the fall migration.
This stage of their journey takes them only to certain marshes, which become stations on their line of travel where countless numbers of their kind, impelled by the flocking impulse, gather to roost in the reeds. Their numbers increase steadily through July and August, the maximum of abundance being reached about September 1st; then they gradually become less numerous, and by October 10th comparatively few remain, though if the weather be favorable, they may be observed daily until late in the month.
Throughout this period—from July to October—the marsh is used only as a dormitory, the reeds evidently offering suitable perches to these weak-footed birds, who in the morning radiate throughout the surrounding country and in the evening return to the marsh to sleep. In the evening they fly low, and the altitude and time of their flight make them conspicuous. In the morning they fly high, as though bound to some distant feeding ground, and at so early an hour that they usually escape observation. The evening flight, therefore, is generally considered as truly migratory, when, in fact, the same birds doubtless pass over a given locality night after night, perhaps for weeks, in returning to their roosts in the marshes.
48. “Bird notes”—Tree Swallows.
These evening flights begin about two hours and a half before sunset, when the birds, after resting during the late forenoon and early afternoon, usually on some telegraph wire,[48] begin to wheel and circle over the fields in pursuit of their evening meal, when one might imagine they were resident birds, but observation will show that the general trend of their movement is toward the roost.