6 mi. N of Pachuca, 9600 ft, Hidalgo, Mex. July 2, 1946 Scrub giving rapid series of scolding notes - "chun-chun-chun". Both of the Wrens collected were members of pairs. 2 Canyon Wrens were heard singing from the ridge above the stream. A Catharus occidentalis was taken from a patch of small fir by the stream. The last bird taken was a Myioborus miniatus, which was foraging actively in the fir tops, about 50 ft above the ground. Junco phaeonotus was seen in all types of habitat during the morn- ing. One Hairy Woodpecker was heard call- ing from a fir in the dense fir woods. Robins were encountered throughout the morning wherever there were trees. July 3, 1946 Left camp about 7 a.m. and headed downhill along the road leading south toward Pachuca. At 9250 ft. the road led past a small reservoir with a dam at the south end. This reservoir constitutes a part of the water supply for Pachuca. At this point there were pines mixed with the fir, and a short ways below the fir dropped out entirely, and oaks started to ap- pear among the pines. The under cover was mostly Baccharis sp. Crossed a ridge possibly 200 ft high, from which the mountain chain forming the eastern rim of the Valley of Mexico could be seen stretching