Invariably among the tamest and most confiding of our so-called shore birds, they will usually permit one to approach, either on foot or in a boat, within 5 or 6 yards, while I have known a gun to be discharged into a flock with fatal effect, but without causing any of the birds which escaped injury to take wing. Like most obese creatures they are habitually sluggish, confining their wanderings afoot to limited areas, and exploiting these very deliberately, walking slowly and sedately in crouching attitudes, with measured steps, frequently stopping to thrust their bills listlessly a little way into the soft ground, or to pick up small morsels of food from the surface. Occasionally, however, one may see them running to and fro over the mud quite briskly and ceaselessly, perhaps incited to this comparatively unusual behavior by the example of other waders feeding close about them, for they are by no means averse to the companionship of several of the lesser kinds, such as semipalmated plover and sandpipers, grass-birds, dunlins, etc. Although somewhat loath to take wing, even when threatened by obvious danger, they are likely to fly swiftly and far, when once started, doubling and circling over the marshes in much the same manner as other small sandpipers. John T. Nichols, says in his notes: When startled, a bird has been seen to crouch down concealing the bulk of its white underparts and practically disappear against the brightly lighted mud flat on which it had been feeding. This is a habit shared by its close relatives the pectoral and least sandpipers. _Voice._--The white-rumped sandpiper is ordinarily a rather silent bird, but its short, sharp flight note is characteristic of the species and serves to distinguish it readily in the field. To me it sounds like _tzeep_ or _tzip_; Mr. Nichols calls it "a squeaky mouse-like _jeet_"; Mr. Brewster (1925) describes it as "a feeble lisping _zip_ or _tsip_, fringilline, rather than limicoline, in character"; and Doctor Townsend (1905) thinks that "it suggests at times the call note of the pipit." C. J. Maynard (1896) refers to "one cry in particular, being loudly given and greatly prolonged, resembling the scream of a rapacious bird more than the whistle of a sandpiper." _Field marks._--The best field mark for this species is the white rump, or rather upper tail-coverts; this is conspicuous in flight but is usually concealed by the wings when the bird is on the ground. I have noticed that, while the bird is standing with its side toward me, the gray of the upper parts extend down on the sides of the neck as far as the bend of the wing, whereas in the semipalmated sandpiper, with which it might be confused, there is a decided white space in front of the wing. Mr. Nichols says in his notes: