The skin of the throat and breast becomes very flabby and loose at this season, and its inner surface is covered with small globular masses of fat. When not inflated, the skin loaded with this extra weight and with a slightly serous suffusion which is present hangs down in a pendulous flap or fold exactly like a dewlap, about an inch and a half wide. The esophagus is very loose and becomes remarkably soft and distensible, but is easily ruptured in this state, as I found by dissection. In the plate accompanying this report the extent and character of this inflation, unique at least among American waders, is shown. The bird may frequently be seen running along the ground close to the female, its enormous sac inflated, and its head drawn back and the bill pointing directly forward, or, filled with spring-time vigor, the bird flits with slow but energetic wingstrokes close along the ground, its head raised high over the shoulders and the tail hanging almost directly down. As it thus flies it utters a succession of the hollow, booming notes, which have a strange ventriloquial quality. At times the male rises 20 or 30 yards in the air and inflating its throat glides down to the ground with its sac hanging below, as is shown in the accompanying plate. Again he crosses back and forth in front of the female, puffing his breast out and bowing from side to side, running here and there, as if intoxicated with passion. Whenever he pursues his love-making, his rather low but pervading note swells and dies in musical cadences, which form a striking part of the great bird chorus heard at this season in the north.
Mr. Conover (notes) adds the following:
When the male rises in the air to boom, in sailing to the ground he throws his wings up over his back, much in the same manner as tame pigeons when descending from a height; also a male which flew by with pouch extended was noticed to jerk his head up and down as he gave his call. The bill was partly open and he gave the appearance of swallowing air to inflate his throat. As it is the esophagus which is inflated and not the windpipe, this in all probability is what he does.
S. A. Buturlin (1907) gives a somewhat different account of it, as observed by him in Siberia, as follows:
One would every now and then stretch both wings right over its back, and afterwards commence a grotesque sort of dance, hopping alternately on each leg; another would inflate its gular pouch and run about, crouching down to the ground, or would fly up to about a hundred feet in the air, then inflate its pouch and descend slowly and obliquely to the ground on extended wings. All these performances were accompanied by a strange hollow sound, not very loud when near, but audible at some distance, even as far as 500 yards. These notes are very difficult to locate, and vary according to the distance. When near they are tremulous booming sounds something like the notes of a frog, and end in clear sounds like those caused by the bursting of water bubbles in a copper vessel.
Nesting.—Mr. Murdoch (1885) says:
The nest is always built in the grass, with a decided preference for high and dry localities like the banks of gulleys and streams. It was sometimes placed at the edge of a small pool, but always in grass and in a dry place, never in the black clay and moss, like the plover and buff-breasted sandpipers, or in the marsh, like the phalaropes. The nest was like that of the other waders, a depression in the ground lined with a little dry grass.
A set in my collection, taken by F. S. Hersey, near St. Michael, Alaska, was in a slight hollow on the open tundra with no concealment. And a set in the Herbert Massey collection, taken near Point Barrow by E. A. McIlhenny, came from "a slight hollow lined with dry grass, in the dry, gray moss of the tundra."