5P Myers 1974 Journal Arroyo Chico, Estancia Medeland, 35 Km S. of Juanicho by road, Pte de Madariaga, Pcia de Buenos Aires, Argentina 12 March (cont'd) Charadrius fulvicaudus numbers were above data from recent past. The large drainage ditch, that flows into the Arroyo between Bar 17 has been augmenting their totals, particularly in the last day or two when I've found numbers of birds resting up amidst the crocipes in a broad flat sandy run — the alluvial plain of the drainage ditch. Today this stretch was also responsible for increased #s of Hudsonian godwits — one flock of 4. White-rump Plover was, as yesterday, found twice. First in the early morning below subunit 1 with a flock, then ~0930 between subunits 6 and 5, suggesting that its flock is again inflating numbers. 15 banded White-rump away. After finishing the banded bird survey I returned to seek Ry Lop on Subunit 7, choosing this bird from others because of its constancy. Took following data from 1032-1132 (see sp accent + following data). The bird is territorial. On returning to subunit 4, I was struck by the difference in WR distribution between then + less than 0.5 hr back — there were many areas with any WR, + several small areas with groups of resting birds (see sp accent). 10mm rain this afternoon. 13 March On Arroyo 0800, began reading linear grid 0813. Temperature 12°C, with no wind, and not only a heavy low fog but high clouds as well. Yesterday afternoon's rain has affected the Arroyo water level only slightly. Grid totals: White-rump 19.20 (31); Charadrius fulvicaudus 99(18); Greater Yellowlegs 01(1); Black-necked Stilt 11(2); Southern Lapwing 9.6(6); Neotropic Cormorant 14.2(3); Shorelark 05(5); Spotted tool 36(9); Aras versicolor 01(1); Maguari Stork 01(1); Brown-headed Gull 13(4); Riparian-billed Night Heron 02(4). Although the rain did not raise the water level very much, it did turn our usual route broad along the Arroyo shore to mud, making running down, i.e., a total count impossible. Therefore I went to linear grid subunit 5 in order to follow Ry Lop White-rump again (1010-1103; see WR sp accent, linear grid following data book p 42). During this period a SANDERLING!! appeared at the school. It was still in basic plumage of no sign of molt. Associated with Ch. fulvicaudus and White-rump. Tower Flumes, Estancia Medeland, Pte de Madariaga, Pcia de Buenos Aires, Argentina After leaving Ry Lop we drove down the Arroyo and out onto Tower Flumes, briefly surveying the area for Snuffin and Threskiornis. None of the former, 5 pecodejus flying in the same place as previous days.