J.P. Muys 1974 Chanaclius falklandicus 26 August (cont'd) Arroyo Chico, Estancia Medeland, 35 km S. of Juancho by road, Ptdo de Madariaga, Pcia de Bs. Aires, Arg. and then peeks 45 cm away from the foot. It has passed through 3 types of that micro-habitat since I noticed this: saturated but exposed mud, 100% surface water, damp sand. It does it only in the first type, but it does not vibrate all of the time. Thixotropic ?? la Orqueta (3,3) on Journal map 8-23-74, Estancia La Atlantida, Ptdo de Madariaga, Pcia de Bs. Aires, Argentina 28 August many falklandicus along the muddy edge of la Orqueta. At least 75 here, with possible 10-15 holding territories. Raptor KOLY present!! Also found another bird foraging as did that described 26 August - the foot shakin' 30 August 1730 - 2-3 small flocks of falklandicus foraging + flying about la Orqueta - perhaps a total of 35 birds. The falklandicus are flying either by themselves (i.e. flocks of pure falklandicus) or with Zenithyx, this means that they are largely separate from the 35 peeps which are flying about, also in a flock. I have seen only 2 falklandicus flying with first group this evening. 2 more falklandicus feeding with the fly-shaking routine. Also noted another type of feeding - a very jerky process resembling a Calidris search-pedal: instead of running several steps between stops, this individual took individual steps and peddled between them. Extremely jerky. Arroyo Chico, Estancia Medeland 35 km S. of Juancho by road, Ptdo de Madariaga, Pcia de Bs. Aires, Argentina 31 August falklandicus are spaced out along the linear grid, with some obviously territorial individuals 1030 I had stopped to watch a bairdi foraging alone with a solitary falklandicus - 3 falks and one bairdi flew in shortly. The latter encountered me aggressively from its already present non- specific. But the 'raintut' falklandicus ran at the intruder from a distance of 20 cm, with quick back lurches, calling 'huét huét-huét, huét da da da, huét da da da'. Despite the rapid response, it took several 'half-hearted' attempts (compared to the ferocity of other Chl. terns I have seen) and several minutes, to force the other Chl's away. 1140 - Lr Ch.f. in territorial between units 6+7 (i.e. 1230). Saw one good supplication, the supplanted bird was then chased again by Lr's neighbor to the S (S) 1 September 1145 - Lr is between 6+7 when it has been territorial for the past few days