J.P. Myers 1974 Calidris fuscicollis (11,16) Arroyo Chico, Estancia Medeland, 35 km. S. of Trancillo by road, Pteo de Madariaga, Avia de Bahía. 19 November % TB calculation #4. See journal. We placed enough stakes to define a 15 x 90 m unit and to allow following data. Rplp A on unit, obviously territorial (and had been so since 11-3 or before). Then an 2 other obvious "in" birds as we began. Occasionally birds are coming through. Mean 10:30 - many border interactions between 2 birds in the lower area of the grid. Lois is following one - 11-19-74 A. 1103 11-19-74 A has been supplanting consistently as reflected in following data. One thing which appears to happen is that when it supplants going into the wind (W) and the other intruder responds by flying across the Arroyo, 11-19-74 A supplants B on the other side and soars down wind to the SE end of its territory, in fact something going below + drawing a supplantation from its territorial neighbor to the SE. This bird (11-19-74 B) just flew over following a soar by A, and although it did not land, it crashed at A and then returned to the place from whence it flew. 'A' chattered also as B approached. 1116 - a flock of goldens + buffis flew over - all grid birds took off except for Rplp. 1120 - 5 wr c.1 1 birds have entered in to A's territory and are not being hunted. However, as they fed directly to the W, and reached Rplp's border, they were attacked + supplanting. 1127 - 'A' pack again and supplanting, so is 'B'. Using same borders, instinct themselves + for intruders. 1128 supplantation involved a classic 'wing-up' very reminiscent of Tryngite. Did the W wind catch a wing-out? 1158 'B' (which Lois has been following) - flew to this side of Arroyo as its southern neighbor came up to edge of territory. 'B' flew over calling, going directly towards the offender. Within 40 sec they began fighting - hopping jabbing, wing flashing - and then went into a border crash for 2 min: S Neighb. southern neighbor angle crowded ≤30cm { [illegible] bill tucked crouch tail up A & B SN came out first, shy backing away, pecking, and it then began to feed. When it was 40-50cm from 'B', 'B' began feeding, going away from SN. See %TB book for data also Linear 97B following for 11-19-74 A and B.