E. humilis 93 May 2-3 - C humilis - Condition of Skull May 3 2150 2153 2156 just about finished 2157 2158 2173 May 3 Collected 19 wrens near camp on the Rio Guemal, 14 miles E Nitufec, 38 m. None were in breeding condition but several were seen carrying materials to nests. I found only pairs a possibly are trio. These birds don't occur in large groups - rather pairs are evenly spaced and only a single nest is built. I saw no situations where 2 or more nests were present. Nests invariably in Bull- hornacacia - mostly 10 foot up or more in crochets. Nest measure ± 10 x 8" - very small and little if any Tunnel - several nests seen looked unfinished. One bird I took today was carrying plant "wool". As at Study Area #2 near Tonalá' the wrens occur in the riparian vegetation such as guanacoster but they reach abundance in the acacia-guanache stands on sandy ground well back from the river. Details the riparian situation is not the central habitat. I found wrens in abundance in almost pure stands of small acacia - Mimosa - small guanaches are