S.P. Myers 1974 Journal Estancia Urdeland, 35 Km S. of Juandio by road, Partido de Madariaga, Proin de Buenos Aires, Argentina 29 November (cont'd) to just above the shoreline - and there almost never unless the substrate is very moist (or it might be given receding water). This year they have not had much of a choice of habitat as most of the marshes are dry. Nonetheless, when marshes were available fusciolis chose places with little emergent vegetation - usually bare mud. Typically, they surface their bill points concentrated in depressions in the substrate. They choose places with a % of algal mat. Other - Calidris melanotos - very few in areas we visited this morning. Almost invariably these foregoing areas have emergent vegetation - in fact, they are as likely to occur or more so in upland fields than as in the Arroyo where there is no vegetation at all. Calidris bailii no more than 100 remain now on the Estancia, the heavy majority of which are in upland short grass with Trigonia. They do occur regularly in the Arroyo, although typically one finds them above the shoreline on dry substrate, even though they do seem will forage in the H.O. (Trigonia fusciolis does supplement bailii, apparently play a role in keeping them away from the water's edge - the population here is nothing. I have seen no sign of territoriality during the last 2 months. - Tringa flavipes - common but very dispersed, as a result of well developed territorial system. This species has also suffered from lack of G-1 habitat, which last year was the typical drying pond cluttered with emergent vegetation (grass + Solanum). Limosa haemopteris - common in the Arroyo in areas with a high proportion of mud (sod) also present in uplands although less than air water for uplands. I've seen them only in short-grass habitat. During several journal entries, e.g., this morning's, I have referred to microhabitat data, which we are taking on the various members of the shorebird community. By that I meant the following procedure: a bird is selected and followed for 2 min (if possible, 2 birds are followed simultaneously). At the end of the following period, I note the next place where the bird places its bill (with a peck, project, thrust, etc.). (Going to that point, I measure