J.P. Myers 1973 Calidris melanotos 2 December Farmhouse Pond (Grid #1), Estancia Wiedland, ~35 Km S of Juancho by road Puciack Buenos Aires Arg. I may be looking at only one Pectoral on the grid this morning. Certainly, flew or recorded in colony columns 25+26 is the same individual. I don't know about the one seen earlier in 18/, as it flew between sampling times, nor and several other 000 sample with Pectoral in 23/2. However the last 4 samples did with the same bird moving 26/5 (1030); ~26/1 (1100); 25/3(1130); and 26/2 (1200). This bird appears to have a spot to which he returns to perch and not move in 25(3) Grid #2 Rte IJ Pond, Estancia Wiedland, Pucia de B.A., Arg. We are here to complete the staking up (Grid #2 at 1300). From the observation post I was able to pick out this Pectoral in the met of vegetation at the far end of the grid, where I have noticed that there is almost invariably a Pectoral. It to resting in the vegetation, two legs folded and breast down. More other visible. However when I approached the edge of the pond 2 others flew. 3 December Just prior to taking the first grid count (0630), at 0615 I saw a supplanting change by a Pectoral near 12/2 towards another that was 9/2. When I arrived here this morning (0600), I had been able to consistently find a Pect near 12/2. This was probably the supplanter, where the intruder came from I don't know. 0810 - Pct. from 15/3 was supplanted intruder in 8/3; remained to feed. Called while flying. 0827 watching Pectoral on 14/3 mat, while peering + fading. He called twice and then flew to the W., landing for less than 2 seconds in 103, then continuing to 8/3 where another Pectoral was. He chased this bird. At that point I switched to the intruder, who flew to 8/1 across the park. It was immediately chased from by another Pectoral, but when the chasing bird came near I don't know. Farmhouse Pond (Grid 7), Estancia Wiedland, Pucia de B.A., Arg. 4 December One Pectoral on the grid between 0600 and 0730 - (he stay) the whole time. No sign of any other Pectorals here. In the process of taking following data I observed one puzzle which can not be interpreted. The bird had been feeding as to 12/3.