JPMyers 1979 Zonibyx mcdougalis 03 Arroyo Chico, Estancia Medeland, 55 Km S of Juancho by road, Ptdo de Madaniaga, Provincia de Bs Aires, Argentina 25 April (cmt's) subunit 6 with a new territory amidst a mounding other territorial Zonibyx, falcklandicus, and even- tin. WR the [illegible] border encounters between Zonibyx are very reminiscent of falcklandicus. Based of 'tail down' as in a scolopacid, the wings are held down, lowered, exposing the tail + the rump. This is what occurs in an intense battle, particularly when the [illegible] wing lowered bird is about to strike the other with its wings. As in falcklandicus the orientation of the 2 birds - parallel, antiparallel, etc., appears to be very important and ritualized. Attack is of a fairly standard topography: The head of the attacking bird is lowered as it runs at its object - almost as if to raise the other in the air. Contact is often made in these runs. And during the wing-killing bouts, the sound of contact is frequent and carries a considerably distance (10's of meters.) 1230 - subunit 4 - flew to a Zonibyx missing the right leg below its ankle joint! It was foraging successfully. 26 April Tower Ulanos, Estancia Medeland, Ptdo de Madaniaga, Provincia de Bs Aires, Argentina 1400 observing mixed flock of Zonibyx + Oreophasis by the south gate. 5 Zonibyx. see Oreop. spacel for comparison of Dr. and Zon feeding behavior. 1800 Arroyo Chico, Estancia Medeland, Ptdo de Madaniaga, Provincia de Bs Aires, Argentina 101920 Ro on same unit of subunit 6 as it was the morning. 40 Km N of Victoria, Provincia de Entre Rios, Argentina 13 August see today's camp list. Several small groups of Zonibyx found foraging up from the water's edge today in the area wrought with cow heaves. A total of 50 Zonibyx more or less, several of them are [illegible] will along the way to bruting plunge, with their chest pattern well developed. Very much aggression; these birds are obviously territorial. 60 Km S of Gualaguaychili, Provincia de Entre Rios, Argentina 14 August one Zonibyx present at the edge of a drying pool. molting. Estancia Medeland, 35 km S of Juancho by road, Provincia de Bs Aires, Argentina 23 August several hundred Zonibyx foraging on Tower Ulanos and other short-grass areas of the Estancia. Most of them in spring plunge. Many aggressive interactions, often within a context suggesting territoriality. Frequently seen display crest of a lunch-back form