Spring migration takes place the latter part of April and the first half of May. My earliest record for St. Paul Island is April 15 (1915) when a flock appeared at Northeast Point. The height of migration is a little later than that date and may usually be expected from the 1st to the 15th of May. Birds are almost invariably paired upon arrival. Very few spring flocks have been seen on the Pribilofs, and they do not tarry by the beaches, but go directly to the upland nesting sites. It seems to be uncommon for more than the resident population to land upon an island in spring. The birds seem to go directly to the chosen breeding grounds, wherever they may be. This fact is of wide application among the northern shore birds. Only rare stragglers of such species as golden plovers, turnstones, and pectoral and sharp-tailed sandpipers stop at the Pribilofs on their way north, but large numbers of some of them come in fall. _Courtship._--Dr. E. W. Nelson (1887) writes: The male of the pair seen by me on St. Lawrence Island in June kept flying up some 10 or 15 yards, its wings beating with a rapid vibrating or tremulous motion, while the bird thus poised trilled forth a clear, rather musical and liquid but hard, whistling note, which is probably the same note which Elliott likens to the trill of the tree frog. The short song ended, the musician glides to the ground upon stiffened wings and resumes his feeding or stands silently for a time on a projecting rock or knoll. _Nesting._--We found Pribilof sandpipers very common in July on the low tundra at the south end of St. Matthew Island, where they were evidently breeding just back of the beaches. They were also common in the interior at the north end of this island and on the highlands of Hall Island. We collected a few specimens of the birds, but had no time to hunt for nests. We are indebted to Mr. Hanna (1921) for his excellent account of the nesting habits of this bird, from which I quote as follows: