JPMyers 1974 Calidris fuscicollis Estancia Medeland, 35 km S. of Tucumán by road, Pto de Madariaga, Provincia de Bs Aires, Argentina 23 August 1010 in the Arroyo part the linear grid (see map p. of Journal) as a flock of mixed bairdi-WR flow by. The former predominate, but several white-rumps flashed and I heard afterject: calls. The first of the season. I only wish that I had been able to be here earlier. We very uncommon w.r. to bairds, which themselves are not frequent. Found a total of 25-20 between the grid and the Rte 14 bridge, all within mixed flocks flying or foraging along the Arroyo. Although they are talking, there is no apparent aggression + certainly nothing space- specific. Collected 2. One not collected still had riddish intermed. scapulars Mouth of Canal Tinto (Laguna Mar Chiquita), 21 km N. of Mar Chiquita, Provincia de Bs Aires, Argentina 24 August a flock of predominantly WR (but mixed w/ bairdi + Micropalama) foraging along the mod flat (see map p66 of Journal). very tight flock, skittish, moving frequently by flying 20m down or up, calling while flying. WR calls the most frequent. Some chatter, but no sign of SS aggression. In fact there was very little aggression, about all that I could detect were occasional down-tips of the tail which accompanied 'head-plunging': e.g. when the head or bill was thrust downwards into the water, either the tail curved down, or the wings would up. Perhaps an individual spacing mechanism. No banded bird Arroyo (Estancia Medeland), 35 km S. of Tucumán by road, Pto de Madariaga, Provincia de Bs Aires, Argentina 25 August at 0815 found a small flock (7) WR at unit 10 of linear grid. foraging along a saturated but exposed mud bar in the Arroyo. Moving as a group. 2 'dropped out' - flying off. The remainder all tight, occasionally one or two falling behind only to run to catch up. Little aggression. Payimg much attention to the calls of other shorebirds, particularly Erythrocyphus and Vanellus: they stop feeding, part-up with their bill pointed slightly down. [a thought: it looks as if adults may winter further south than juveniles (only because I had mostly juveniles here last year). If the adults arrive here before Erythrocyphus, Oricopelus, etc depart for the south, and if they join them in flocks, then they may keep moving, whereas the juveniles arriving after the Erythrocyphus, etc. elegant might not be so endured. (only a thought)] Feeding is almost all scratch- peck. every one in a while a head goes all the way into the water. Never any filter-feeding. 0825 the unit has been breaking down. The 6 are spreading out,