J P Myers 1974 Journal 62 Mouth of Canal 7 into Laguna Mar Chiquita 21 Km N. of Mar Chiquita by road, Pdo de Mar Chiquita, Provincia de Bs Aires, Argentina 2 April (front) the 'submouth' of the Lesser Canal 4 channel, are small 'islands' of floating vegetation (the name of which I don't know, but it is characteristic of many swamps in the Province, forming a dense mat. The plants are small, of less than an 1" in diameter, + multicolored (some red + some green). These 'islands' are never larger than 4' or 5' across, usually 1'-2', of very convoluted form, + separated by water varying in width from 2" - 8". Water depth varies from 0' to 0.5' to less than 1' cfp over a large % of this canal delta. Beyond the flat sand-mud bar it gradually increases in depth, or I after ~150 m there is a sharp break in bottom type - it becomes deeper, at low tide water, broken by a multitude of mud mounts (see 21 March). Someone has conveniently placed a water depth marker out on the flat ~ 200 m from shore - at 1820 it read Red I. Shorebirds covered the flatter delta over 500 m², dispersed in 2 flocks [one at the mouth of the lesser channel, the other at the tip of a large sand island to the N]. Also present: 100+ Hudsonian godwit, every BUSTED, as many as 50 each at Yellowlegs, Chardaruis falllandicus (100+), over 50 Micropalama, a few Southern Lapwing, B-10 flamingo, 20 spoonbill, Cocoi heron, Common egret, Red Shoulders, YB Pintail, Speckled teal, Coscoroba Swan, Black Necked Swan, Black Skimmer, Telp gull, brown-hooded gull, Southern Screamer, Maguari Stork, Cinclus fuscus, Lagonia rufa, White-rumped Swallow, Cliff Swallow (1), Phleocryptus A rough map of the area: The saddle is only rough - N-S dimensions are somewhat compressed with respect to E-W. mud bank higher land N shallow skimmer island deep water break in bottom type gridded area mud flat shallow tidal marker Tide mud flat Canal 4 Canal 7