J.P. Murray 1974 Journal Arroyo Chico, Estancia Medeland, Ptdo de Madariaga, Provincia de Bs. Aires, Argentina 30 September (cont'd) 0745 entered the leucar grid area in order to fit work on stakes and to search for banded birds. We drove along the east bank from (0,13) to (13,24). At (13,24) we repaired subunit 10 and placed a new grid in the area between subunit 10 and the fence to the north. This grid measures 50 x 15 m. Territorial white-rumps continued to compliment from the area as we pounded stably. See resighting chart and sighting accents for its seen in Arroyo. 10 October (13,24) Arroyo Chico, Estancia Medeland, Ptdo de Madariaga, Provincia de Bs. Aires, Argentina barking again - reached subunit 10 - grid 13 at 0745. Temp 2.5°C at 0330. 0 clouds, no wind. At several places along the Arroyo I came across roosting Pluvialis d., and suspect strongly that Calidris was roosting there as well. There was a large flock of places at 13 when I arrived. 3/14s were up by 0530, shortly after first light. I caught 2 Pluvialis in the 1st net while pulling up the 2nd. They were the only birds to fall this morning: fuscicollis and Bairdi appeared only after light levels were too high. In fact Pluvialis did not start calling very much until 0550. I suspect that the heavy frost may have affected the birds' daily time of arrival. Even after the came, many remained stationary, feeding (particularly upland Pluvialis) the large flock of Bairdi, which I often see here foraging in the up- lands with Pluvialis foraged along the upper reaches of the sand banks of the Arroyo until after sun-up (and frost melt). A very unproductive, but beautiful morning. 2 October 0900 L mod W wind, clouds 55%, temp at dawn = 3°C. I entered the Arroyo at (6,13) and drove north. See sighting data for its seen. Species: Vanellus, Himantopus, Pluvialis d., Charadrius falklandicus, Charadrius collaris, Calidris fusc. + bairdi, Tringa, tringa, flavipes, Steganopus tricolor, Micropalama himantopus. Took micro data for fuscicollis, Ch. falklandicus, and Micropalama. See WR supplement re definite territorial birds.