J P Myers 1989 Calidris fuscicollis Arroyo Chico, Estancia Medaland, 35 km S. of Ivañacho by road, Pto de Madariaga, Provincia de Buenos Aires, Argentina 13 November (cont'd) spice-specific in aggregating. However, here again there was a large n-s.s. component. I had the impression that a few birds were more so than others - distinct impulsion - and that these were largely responsible for the overall order. Beyond zone B the birds became much more separated and n-s.s. Collected one (174) after 30 min observation. In zone A they are also truly s-s. collected one (115). The further from zone B, the more s-s the birds seemed, also, the less dense were the individuals. which came 1st 14 November returned to 15,23 at 1120. density way down, much I did not stay to observe (17,28) Arroyo Chico, Estancia Medaland, Pto de Madariaga, Provincia de Buenos Aires, Argentina 17 November 0830 began censusing for %TB calculation. see journal. great deal of activity by those we present when I began. Earlier during the morning I had taken 2 microhabitats and placed stakes defining the grid. At first glance I noted that some were within the vicinity appeared to be fun, but that others were not obviously so. Because of the topography of the area + the general drying processes going on in the Arroyo, it is possible that this area has been recently invaded. Certainly, on 13 & 14 November the censuses were specialized: 0830 - appears to be ten birds in (2,0), (3,1), and (3,0)-(4,0)-(5,0) (5,1) region but as yet is very complicated. 8 supplemental birds already in the (3,1), (4,0), (4,1), (5,0) (6,0) region (see plot of sites of aggregation in %TB data code. one bird, 11:57-19 A daily unit of the aggregating. also a lot of aggregation in the central area (2,1) ok (but is not clear if s-s. - largely because of the % of birds pulled in from . perhaps area where s-s. in developing. focalizations are occurring constantly. 0845 - not able to keep up in recording %TA. aggression in non-territorial areas. 0917 - rate of aggression quieted down considerably. perhaps a max. now of 2 ten. birds run out at n/5. the rest are showing some intermediate behavior - dance from inconsistent distances, circling, tail up, etc. But Any are slowly drifting the locus of foraging downstream toward (1-12-3) A (center