SPMilers 1974 Tryngites subruficollis Tower Llanes Estancia McIldand, 35 Km S. of Juancho by road, Pto del Madariaga, Provincia de Bs. Aires, Argentina. 18 January (cont'd) Toward "offending" bird. 1923-25 cow walked through yard - no effect on buffleis. 1924 A' tolerated approach of other bird - nawk 20 m into territory. Came as close as 70 m to A. 1930 - buffle landed 40 m from A. A flew, landed within circle of said bird, causing "intruder" to fly 5' to NE. A followed intruder for 5 min with no further aggressive action but then began working back towards edge of area. 1940 - 107 buffleis within 200 m Two main groups, on near grid II + the other in EWE direction. 1949 - definite impression that buffleis are coalescing into smaller & smaller areas, forming flocks, diminishing territorial system. No aggression since 1930 despite close proximity of buffleis. No wing flapping, chases, etc. This trend was shown beautifully in the 2000 Grid 4 sample, when compared to other collie samples. This, despite the fact that the birds continued to feed. 20 January Buffleis not present in tower area when we arrived at 0515 (but arrived entrance ~ 0535). 0615 much aggression both on and off of grid, making it difficult to keep up with movements of the birds. Since 0600 a buffle has been maintaining a territory in 4b (0,0) [southern portion]. Within 11 minutes two supplanted 7 times - all buffleis intruding within its area. 0613 squad rushed at intruding buffle. In contrast to previous 7, this newcomer stood its ground; fight ensued. Reached highest altitude - 4'5" in air during hopping (why the height vary increases?). R then left vicinity, going to lower right (SE) part of (0,0). But 0619 R was pushed further by another supplanted buffle just (1,0). After 2 min R flew back into original area, supplanted a bird (the same one?) that was there. Area it is defending now is much larger than it was the first onset (it appears). Consistently chasing other buffleis away, but ignoring (R) 15 observations since 0605. 0630 - 11 buffleis between tower and 9.0 of 4b. 0651 Buffle landed + another buffle ran towards it, the latter bird holding up its left wing while running, the wing was held vertically [illegible] running. The other