J.P. Myas 1974 32 Tryngites subruficollis (518) Estancia Medeland, 35 Km S. of Juancho by road, Ptdo. de Madariaga, Provincia de Buenos Aires, Argentina. 14 September see evening expedition in journal re roosting flights. (918) region, Estancia Medeland, 35 Km S. of Juancho by road, Ptdo. de Madariaga, Provincia de Bs. Aires, Argentina (measuring this morning I found a flock of 21+ Tryngits by the deep depression at (1,30) at 0920. After finishing the census I returned to observe (see journal for results). 1010 - buffets spending much Time preening also speaker than morning than they have been. 1011 - vichwing by lapwing. 1012 - buffie flying infrequently. always when bounded by lapwing, but also at other times, some of them are erratic, individual flights huge right bird swirling and whirling, etc. - flying low, dashing up 20-30-50 m, then diving twisting in flight. infrequently, as now, a pair will go together. usually it is only one bird. 1015 - This morning I have seen 2 types of movement in foraging buffie flocks: the first is ordered that in which a small group (4-5 6-10 birds) forage in @@@@@ constant direction, moving as a front across habitat, it looks as if different birds lead the group (i.e. are in front at different times, but more often than not they are strong in a line ⊥ to direction of travel. motion → individuals → their orientation is parallel. there are occasional, indeed not infrequent deviations, but not enough to subvert the consistency in motion. The second type is a more static formation, with the flock staying within a fixed area. there in three cases there does not appear to be a prominent foraging director. Often in these there are preening individuals. Question: does one flock switch modes? 1032 very apparent buffy 100m NE of me. 2 fighting, one chasing others away into neck-up-stretched. very consistent + persistent. Wing flashes (single wing) is there a territorial bird? I am too far to get a good spatial perspective. behaviour tape. looks good. birds fighting. 1037 - everyone flew. oh well. 1039 they landed nearby but not on the same site. It looks as if the car + I are a disturbing influence. Territorial Phovialis nearby (see op. cent) 1045 flying again. some almost landed at old site, but took off again just before breaking down. Vanellus chasing buffilio again. The distribution of lapwing