K.Selander, 1952 3 Campylorhynchus brunneicapillus July 24 4 mi. Dapaerto, 5700 ft., Guanajuato, Mexico - Hunted from about 9:30 until 1:00 P.M. Where not common in the tema cortus; very widely spaced; occurred in pairs or groups of 3 or 4, one group every 200 yds or so. Rather mild and difficult to approach; will come to a squeak only when you are concealed from their view. In one spot near a brick fence, I disturbed 4 from the ground; they flew into the dense vegetation; collected two by squeaking them out. No definite indication of territoriality; the birds moving about over long distances. No nests seen. These were apparently do not flip the tail up over the back as is often done by house wrens. Females collected had cava 1mm.; males with testis 3-6mm. The brood. patches of the females seem to be not fully calcotrous. No young observed so it is probable that the young are still in the nest. Lamb says that these wrens occur in the cortus at this locality throughout the year, so presumably there are resident birds which I observed. The nests may be concealed in the thick vegetation. Lamb mentioned having taken eggs of this wren at this locality. The wrens show a definite preference for the areas of dense vegetation, being absent from the more thinly vegetated slopes. Calls uttered by these wrens much more varied than those given by the single adult at the nest near Camargo. The "cha-cha-cha-cha etc."