Page:The Scientific Monthly vol. 3.djvu/240

From Wikisource
Jump to: navigation, search
This page needs to be proofread.


INSECT MIGRATION 235

merged area and only turn west, presumably, after passing around its perilous waters. Still the waters alone hardly seem sufficient to account for this northward diversion, as the greater reaches of the bay have been essayed without hesitation. Probably the true reason, then, is found, at least, in part, in the greater food supplies to be gathered along this wooded river-shore. For here the "monarchs" settle and feed; dragon- flies hover in midair apparently gathering food, and even the swallows dip and glide as if refreshing themselves according to their usual habit.

This solution is further upheld by Dr. Bishop's careful studies in bird migration near New Haven Harbor, a quite similar body of water ten miles farther east. For here he saw repeatedly, not only swallows which are day migrants, but, also in the early morning, such nocturnal travelers as the bluebirds, robins, warblers, bobolinks and many others, nearly all of which were flying north or northwest along the eastern Harbor Shore. And, although he concludes that they were merely avoiding the wide waters, it seems more probable that they were hugging the land in order to feed after fasting through the long night journey on the wing. Moreover, so close is the parallel, in the writer's opinion, that further scrutiny should discover an insect route along this New Haven shore corresponding to our September flight- way by the Housatonic.

Still another butterfly migrant, the "great sulphur," often follows our Connecticut highways as well as the southern Eastern Shore. But this beautiful southern visitor is so fluctuant in its appearance and, at least beyond the forty-first parallel, is usually represented by so few individuals, that its summer sojourn passes almost unnoticed, and only the patient watcher of our autumn lanes of travel may catch brief, infrequent glimpses of its departing yellow wings.

In southern states it pursues regular, inland trails as well; for records recently communicated to the writer are so superior to any hitherto offered that they form a definite basis for further discover}\ While resident at Mt. Nebo, Arkansas, my correspondent, Mrs. Jessie Rose Smith, was the interested observer of autumnal sulphur migra- tions toward the southeast for a period of ten years ! It is true that the same observer has seen other southeastward flights in North Carolina and Alabama; still other students have reported similar movements in Alabama and Georgia as well. But they extend over a very brief period, and even another reference by Scudder, who quotes observations extend- ing over a period of twenty-six years, is so vague in regard to place and direction that it has a secondary value.

But the Mt. Nebo flights, on account of the vast numbers in- volved, the constancy of their appearance ("we could predict their coming for days beforehand") and the uninterrupted sequence of the movements which began in late August and lasted for many weeks —

�� �