JPMyers 1974 Journal 59 28 March (cont'd) Punta Raga, 15 km W of San Clemente del Tuyu, fly road, Pde de Guadavalle, Pte de Bs Aires, Argentina at the lagoon where our path ended we found a flock of mixed shorebirds, some bathing, some feeding, other roting, of over 100 birds. It was comprised of Calidris fuscicollis (50); Calidris alba 5; Arenaria interpres 2; Haematopus palliatus 5; Vanellus chilensis 2; Pluvialis squatarola 3; Charadrius fulvicaudus 50; Tringa melanoleuca 2; Limosa haemastica 6; Himantopus 3. In the vicinity were flocks of the hirundinacea type, as well as trudeani and sexual maxima. Also heard brown-headed gulls. Then during our return we encountered another roosting flock, all birds roting and preening about 30 m from the shore line. In this were falklandicae (80); fuscicollis 90 (80-100); alba -5; canutus (8); interpres (3); squatarola 1. Falklandicae were the only ones remaining active - they were mainly about the periphery of their group (except for some in the main body roting with their body on the ground) with considerable agitation behind them. The roosting site was a 25 x 150 m sandy flat opening in the dunes which had been filled recently by wave action (the 'considerably above the tid line'). It was surrounded by dune grass, except for the sea-ward side which was largely unenclosed. Where did the birds come from? - they obviously were not foraging along the nearby stretch of beach. Although I did not see this quantity fly in, while we were walking S and particularly W, while we were nearing the flock found at our 5-most point - I kept noticing individuals flying over from the SW direction of the extensive mud flats to the NW. At 1545 tide changed perceptibly, and is definitely going out. At 1640 detected first shorebirds - white-rumped flying along the beach. We have come to a stretch of flat NW mud flat 1-2 km W of the tip of Punta Raga, reachable by road after 8 km (about 3 km) toward San Clemente. This is the area where this morning I thought that I could detect large quantities of shorebirds foraging. At high tide there is no exposed beach, but united a steep bank separating the water from a group of fig trees (100 m), plus other assorted shrubs + grasses, including several flats of Salicornia. The 2 WR seen at 1640 were quickly followed by 5 more shorebirds - 3 WM, an alba and a falk- landicae. By this time up to 25 m of sand and mud were exposed in several places along the 700 m of flat mud bank, although most areas had been exposed by considerably less. Wind this afternoon is light to moderate out of the South, with a 10% cloud cover. In several spots along this stretch of the lagoon miniature estuaries flowing to the main body of water. As the tide lowers, the empty, almost completely revealing mud flats of varying size. One such estuary was considerable size, over 100 m