[SBB] "Flock" of Stilt Sandpipers in New Chicago Marsh

From about 11:30 to 12:45 today (8/31) Frank Vanslager and I were busy dealing with the fact that we had at least four and probably five STILT SANDPIPERS in the pond south of the railroad tracks that run thru New Chicago Marsh and just before where the tracks meet those that run into Alviso. This initially did not seem possible (I seen two different STSA in New Chicago Marsh before but never in such a small area), then when we finally left we found two more STSA on the north side of the tracks and east of the pond (none of the 4 or 5 initially seen had flown).. Most of the STSA seemed to be juvenile to me with "bright" white edges to feathers giving the upper parts a uniformly scaly appearance, they had rufous edged tertials and rufous edged feathers at the edge of the mantle forming a "V" on the back, bellies were pure white and the chests were buffy and streaked, Bills were dark, long and bent slightly near the tip, legs were yellow-green. Initially as we approached the pond Frank noticed a breeding plumaged DUNLIN (with a hurt leg?) and standing next to it a Stilt Sandpiper. We then spent some time trying to photograph the STSA. The STSA then flew to the far side of the pond. "It" was re-found and we then noted there was a second STSA (we were watching two different birds). Unbelievably we then found at least two more STSA (some were sleeping, at least one was having a hard time waking up and others were feeding Dowitcher style with there tails held high). We also noted that there must have been at least an inch difference in size between a couple of the STSA (the larger also looking bigger-heavier to me). One of my guides says that the bills and wings of females average a bit longer. Frank felt that at least one of the STSA was an adult, unfortunately I didn't make note of the bird.