J.P. Myers 1974 Calidris fuscicollis (23, 32), Arroyo Chico, Estancia Medeland, 35 km S. of Juanico by road, Pto. de Madeniring, Provincia de Bs. Aires, Argentina 27 November (cont'd) The flock, including RgLy, has speckled; the birds (66-30 in total), have worked back to the same site — you could say that they were foraging directionally, although the directionality line is inseparable from the natural polarization of movement provided by the physical characterization of the Arroyo itself. When the birds reach areas in which we had been seeing S-S aggression, S-S aggression regrouped again. Furthermore, RgLy has returned to the same 1m x 1m patch of algae + mud. Thus, some order reigns beneath the confusion that we can be so overwhelmingly to an observer. And on that 'patch' — it is consistent in supplanting as a S-S median, not usually key individual space attributes. Other birds within the flock are less so; they appear to bounce from one another, pushed by birds behaving like RgLy. Aggression is intense — very quick (one + two) crowdley, tail-ups, tail-downs. And the chatter is incessant. I began a series of 35 min still photos of activity. Also of interest this morning is the fact that as one proceeds upstream, birds become less dense, and the spacing more even + consistent. This is also true downstream RgLy ↑ concentrating flock → areas of increased spacing thus the overall dispersion — a center with outlying areas of increased spacing + S-S — is very comparable to the 13 November conditions. [illegible] In this way, because the central area birds show intermediate behavior patterns — both in terms of an average bird, & in fact individuals — show intermediate behaviors, the behavior of the central area birds has many attributes of space-specificity.