R.K.Selander, 1953 Campylorhynchus brunneicapillus 20 mi. E El Rosario, 1500 ft., Baja California Feb. 4 - Following data obtained from a nest found in a Opuntia cactus 4 feet from ground: 7 x 6 inches - entrance along long axis Entrance oblong [diagram] 1 1/2" 2 3/4" Nest consisted of the small flowers (dried) & some plant having a cotton like appearance. Mattled into this was grass and thin fibers of other plants, some small twigs (very few), piece of paper, and two small pieces of cellophane. The nest appeared to be layered concentrically. The inside was thickly lined with contour feathers of the California quail. A few wing feathers present. Several feathers actually within the body of the nest also. - No large twigs. Feb. 5 Collected three cactus wrens 19 mi. E El Rosario, 1500 ft. Wren occurs in small groups 3-4 in number. After one is shot the other scatter and become silent so that it is not possible to collect more than one specimen from a group. Flights of up to 75-100 yds. are common. Call notes are given when birds are undisturbed. This must be the cactus wren's song. Heard a wren give a few single 'cha-cha-cha' notes today; a bird I believe was disturbed by me. - The groups are sparsely distributed, perhaps one per 200 yds. along the slopes of the arroyo.