JPMigus 1974 Journal 26 Linear grid Arroyo Chico, Estancia Woodland, 35 km S. of Trencho by road, Pato de Machiaga, Provincia de Buenos Aires, Argentina 16 February at subunit 5 by 0530 for banding. Temp = 13°C. slight SW wind, 100% clouds, the cloud cover began to ease No red-winged or spotted tinamou calling anymore. over at 0345 while we were still in camp. Because of 100% clouds, tiny but sun but horizon was impossible to determine, but must have been between 0300 and 0715 ADST. First light detectable ~0620. When we changed up the Arroyo to subunit 5 (leaving Arroyo at 0510) — this were southern lapwing, Chandrius falcklandianus, we saw a spoonbill, but no white-rumps. First CWR heard at 0640. Noted 5 WR and 3 Ch. falck, banding all of them (per band schedule). Had nets drawn by 0800. Unlikely to get the end of the linear grid, subunit 10, and at 0840 began sampling. First sample took 1 hour. We then drove to the S end of the Arroyo (where it leaves tower llanos) — took about 1 hr. (watching 6 Neotropical cormorant fishing upstream — herding the fish, it would seem, a la Baathalornis, in water barely deep enough to hide their backs) + then circuited total grids along the arroyo as yesterday. Totals: (Fence — bend, bend to grid, interior grid) 10:00 AM–11:05 AM White-rump 22,0,56; Ota Buff-banded sandpiper 2,0,0; Hudsonian gull 1,0,0; Greater Yellowlegs 3,0,0; Golden Plover 10,0; Chandrius falcklandianus 16/3/48; Southern lapwing 5,0,16; BN Shelt 0,0,3; Brown-headed gull 8,0,17; Neotropical cormorant 12,0,3; Southern screamer 2 Cocoi Spickled teal 0,0,20; Tern 1,0,0; Rufous-backed merganser 3,0,2. I have divided the count as I have been doing in order to 1) separate out the linear grid densities, and 2) to make the count comparable to yesterday’s taken 100 m S of the linear grid (the second measurement) was included in the linear grid count. Henceforth this 100 m will be included in the 1st measurement Disfainers were sampled for each minute interval: 1 km, 100 m, 3 km. At 1130 we ran the linear gird again. While making the count (for which totals are given above) a concentrated effort was made to grid banded birds. Results: R orange L yellow in subunit #8 6. it flew upstream 150 m; Red L red between subunits 2+3; R yellow L green — on territory as before; R yellow L yellow, green — grid 12; R yellow L orange, yellow — grid 12; R yellow L orange-yellow, beyond grid 12. A total of 6 banded birds out of 56. 1130 - 9 when chicks + 1 adult in field east of subunit #8. Grid totals (2 samples, 1 km of Arroyo spread over 3 km (100 m every 300)): White-rump 24(24)48; Chandrius falcklandianus 19(15-23)38; S lapwing