JD Myers 1974 05 Oreopholus ruficollis Estancia Medland, 55 km S. of Tandil by road Pto de Madariaga, Dicia d Bs. Aires, Argentina 23 August Oreopholus all over the grassland! I mostly in short grass, especially on the NE part of Tower Landa. Several times I have seen a curious almost Columba like sliding in birds flying alone or in small groups. Actually the flight is a combination between the Columba wing attitude, Thinocorus wind display, and Vanellus wing-keeping. 2 September today it is obvious that Oreopholus numbers are decreasing. None on Tower Landa, and few further up the Arago. I saw no more than 50 today total, despite the fact that we went through prime habitat. During late afternoon we went as far as (23, 32) and found denser concentration of Oreopholus. 4 September 1630 p.m. stopped car in midst of Oreopholus flock in (0,18) [see journal]. After 20 min the foraging Oreopholus began approaching the car within 20 m. there were approximately 40-50 within a 200 m radius of the car. No Zonibys, 6 Pluvialis, No Tryngite. 1655 first instance of Oreopholus aggression I've ever seen: a Kiskadee (Pitangus sulphuratus) was the object. Did not see the beginning so am not sure which approached which, but the main behavior once the incident began was Oreopholus [I think that Pitangus flew at the O.] largely because ~10 min ago I noticed an Oreopholus with a large bug in its mouth being followed [both flying] by a Pitangus. The Oreopholus lowered its neck, then, unfurled back feathers, and spread its wings out with its legs bent. The adult wings were not fully extended. Result: [sketch of bird in flight] In the sketch the bird is facing out of the page, i.e. at the Pitangus less than 30 cm away. I could not hear anything, but it may have made a noise. It ran toward the Kiskadee like this. 1700—again today. I am seeing Oreopholus foraging almost without any reference at all to the position of other Oreopholus: they cross-cross on another's path, forming groups, breaking them — a constant shuffle without aggression. 1703 — another Pitangus attack!! The Kiskadee flew at the showbird, which crouched about a meter away, -facing the Pitangus while the latter faced away. They maintained this for ~30 sec + then the Pitangus flew. 1710 — I notice that foraging Oreopholus will