R.K.Selander, 1953 Campylorhynchus brunneicapillus San Telmo, 600 ft., Baja California, Mexico. Feb. 3 Cactus wrens found around the town of San Telmo in the tuna cactus-desert scrub vegetation. Most of the cacti here are small, rarely reaching 4 feet in height. Cactus wren heard calling "cha we cha we cha we cha we cha we" - much like a small car starter turning the motor over. A rhythmic call. Voice seems rather higher than that of gnatlatus. This is the only call I heard. Two birds present. Both flew to nest tree when flushed some distance away. One gave the call. I shot it. Other bird (ad. ?) seemed confused and I was able to approach and callent her also. Territories apparently not well defined, if established at all. These two birds flew 50 yds. or so from nest tree when disturbed. Extremely wary and will not respond to imitation of their call. Become silent if pursued. I do not believe this call has a warning function. Rather I suspect it is the "song", since it is given when the birds are undisturbed. Only saw two cactus wrens. Perhaps there was another present. This pair had inactive gonads so apparently the nesting season is not yet underway. Found two nests of this pair. One was located about 5 feet above the ground in an opuntia cactus and the other was located at the same distance from the ground in a neighboring tuna