J.P. Myers 1974 Journal The Tower, (J18). Sotanica Medaland, 35 Kms S. of Juvando by road, Ptdo de Maduringa, Provincia de Buenos Aires Argentina 21 October With a late start I reached the tower this morning at 0830. Has driven me out and then left with the car. Until 1030 I remained in the blind writing note. At that point I began to sample grids. Since the last tower observation period (see journal, 15 October) we had placed a new series of stakes, finishing the grid 16 set and adding a new grid, 17a and 17b. [Diagram] 16c and 16c are identical to 16a and b; 25x25m with 5x5m subunits. 17a and 17b are 75x75m with 25x25m subunits. 16a and 16b lie within them as indicated in the diagram. After some practice, and using the stake on 16a and b, and landmarks in the 5x5m subunits (large copping an anthill, armadillo digging - very prominent indeed in this habitat) I was able to locate with a fair ac- curacy any bird to within 5x5m subunits on 17a and 17b even if they fell outside of the 16a orb limits. Thus all samples are now taking showing the position of each individual in the grid (see grid linkback). After a few attempts to sample 17a and 17b concomitantly, I decided to concentrate on 17b as to record aggressive interactions in space in addition to the sampling, which were taken all day at 15 min intervals. Grid table: 17b 32 samples Tryngite subnigriollis 7.0 (0-17) 224; Pluvialis dominica 4.6 (0-10) 176. No other shorebirds were recorded on the grids. During the morning grid 17b was the scene of considerable instances of supplanting; None were largely limited to several areas (see aggression site chart). At 1330 everyone spooked, many congregated in 17a (for which I have 2 readings at 5 min interval) but within 20 minutes what appeared to be literally all the buffle and most of the Pluvialis from the (J18) region - i.e. the considerable radius of vision that I have from atop the tower - flew towards the array. They began reappearing in double ~45 minute later - small flocks of buffle and other flocks, but mainly solitary, golden. The first traffic reappeared on 17b at ~1528 and immediately picked them up