By the 10th of August all the young are well able to fly and make protracted flights in search of food. By this date they assemble in flocks, amounting at times, to thousands of individuals, resorting to the mud flats left bare by the receding tide. The mouth of the Koksoak and the cove to the westward of it present excellent tracts of mud deposited in the little indentations. By the middle of September these birds begin to depart to the south. Many of them ascended the Koksoak and others doubtless followed the windings of the coast down the Atlantic. I have seen numerous flocks over a hundred miles from the mouth of the river as late as October 12th, and an occasional single bird as late as the 20th of that month. I have observed, at the mouth of the Koksoak River, flocks of these birds often numbering over a hundred individuals suddenly appear from high in the air. These I suspected to be birds coming from the regions to the northward of the strait for they always came from the sea. Thence there is an overland flight to the Atlantic coast. Mr. Brewster (1925) says: White-rumped sandpipers visit Lake Umbagog regularly and not infrequently, if rather sparingly, in autumn, appearing oftenest during the month of October. Those arriving early in the season are mostly adult birds which occur singly or two or three together; those coming later are of various ages and sometimes in flocks containing as many as eight or nine members each, but rarely, if ever, a greater number. Bonaparte's sandpipers are hardy birds. They may be seen at the lake when its bordering marshes are stiff with frost. Once (October 26, 1883) I found nine of them near the mouth of Cambridge River two days after the entire region had been covered with snow to a depth of 7 inches. This bird is a regular, but never an abundant, migrant on the coast of Massachusetts in the fall. The vast numbers which Turner saw in Ungava must seek some other route; the species is never abundant in the interior in the fall and it seems to be rather rare on the Atlantic coast south of New England; the natural inference is that it migrates at sea from Maine or Nova Scotia directly to South America or the West Indies. It is abundant at times in Bermuda.