JPMeyes 1974 23 Trying to subadult collie Tower Claws, Estancia Medland, 35 Km S. of Juancho by road, Pteb de Illadariaga, Provincia de Buenos Aires Argentina about to take to flight. It occurs to me that the relative position of the aggressor and the aggrieved causes the two birds to receive very different sights when the two of them extend their wings: the aggrieved see the white under-side of the aggressor, which in turn sees the brown top side of the aggrieved wing. 0913 - good flights on the beach - a hopping + ginning flight lasting for 5 seconds, ending with one flying away and the other remaining to feed. However, situation at Claws remains the same with little or no aggression. There may be a territorial bird beneath the tower or slightly to the East. 0919 on Grid 10 2 buffleis feeding quite close together. Allala scalds are started chucking and running at the other neck held stretched at an odd angle. 0950 - I've been struck by the amount of preening and wing stretching in which the buffleis engage. Would appear to be more maintenance activity than last month, especially directed towards wings. Following Dita: Lou began following buffleis at 0730; during the subsequent 25 hours she followed 9 birds (see pages 43-48 Grid 10 notebook) continuously. No bird remained within the vicinity of Grid 10 for more than 22 minutes; they averaged 12 minutes. Alas! Although the birds may have been leaving the area and then returning, the following data show a very different pattern today than they did last month. No centers of activity, at least on the scale of Grid 10. A small flock of birds, ranging from 2 to 4 birds "sweep" (by walking) through the grid area, continues fairly directly across the grid and out again. Rate of movement of the birds appeared to be faster too - although the exact comparisons await more accurate treatment of the data - it appears that the birds travel farther each minute. Following data also reflects the little aggression which we saw. 26 February On tower at 0645 First buffleis detected at 0713. First bird entered Grid 10 at 0715 0717 saw probably 15 buffleis flying in, 8 flying across range. I.e. birds are still dispersing from roost, it would appear. 0735 - buffleis still coming on the grids - flock of 9. 0740 - the buffleis are herding again. It appears as if they are single traversing a shared transect instead of a linear territory as last month: they walk along, continuing off the grid. A few minutes later another group appears, about the same size as the previous one, which goes on, through and off the grid again. 0745 - there is also a lot of flying today. Very little aggression. 0810 not only are there buffleis on the sand, in numbers, as they were yesterday, but they also reach down onto the edge of the array water - feeding, bathing, drinking.