J.P. Myers 1974 Tryingite subruficollis 69 Grid 17b, Tower, (1,18) region, Estancia Medaland, 35 Km S. of Juancho by road, Ptdo de Madariaga, Puicia de Bs. Aires, Argentina 20 November difficult to detect some of the more subtle interaction, particularly since which we used frequently between territorial neighbors. That that the indicated areas are used by territory birds law certain, but precisely when the boundaries are less clear. [See Grid 17b data book for samples, and Grid 16-17 data book for plots and timing of aggression.] (4,15) Estancia Medaland, & Ptdo de Madariago, Puicia de Bs. Aires, Argentina 21 November 0830 - taking microhabitat data on buffico we spotted a bird supplementing consistently, from an area of open shorter grass surrounded by a thistle ridden patch (even tho' buffico were in the thicketed areas as well.) as we watched a directional flock moved into the territory and the bird supplemented all corners. Collected. Note that this individual did not employ wing flares or tail-downs. All we saw during ~15 min observation were helicopter flights and side-head supplement. Grid 17b, Tower, (1,18) region, Estancia Medaland, 35 Km S. of Juancho by road, Ptdo de Madariaga, Puicia de Bs. Aires, Argentina 22 November Began sampling 0900 see journal, grid 17b data book, grid 16-17 following data book for timing + location of aggressive acts. 0920 - bird flew over (1,10) to (0,1) unit of 17b from S., near middle, and as it landed it precipitated supplement #7 (see plot data), in which the supplementer flew 25m from just W of (0,0). Supplementing force = helicopter flight. The bird individual flew off. The helicopter bird then flew to lower right of (0,0) unit, clearing other bird out of (0,0). This provoked a supplementer by 0,1-16b bird, which flew at original supplementer, helicoptering. As 0,1-16b helicoptered in, the original supplementer landed, gave a tail down. to us, in the tower, at an angle not dissimilar to that of the approaching, supplementing bird, the black central tail patch was very obvious in this display. The pair then had a hopping flight, and 0,1-16b successfully supplanted the other, which flew back to the center of its territory. 0,1-16b continued feeding in that area going W. after 3 min later, the original supplementer