LL Wolf 1963 Aimophila humeralis July 28 8 mi. NE. Autlan, Jalisco, Mexico #2604 - body plumage fresh. molt on back. flight feathers worn Found this species to be rather common on first hills NW. of Autlan. First located by chattering which is similar to A. ruficanda but seems to be higher + less harsh. At 0630 mostly seemed to be in pairs. At 0730 we tried to collect some + found groups up to 4. These appeared to be natural groups as we chased after hearing chatter + did not push birds around much. Vegetation preference is hillside covered with almost to entirely closed canopy of thorny trees averaging about 15 feet high. Once had A. humeralis + A. ruficanda within 10 feet of each other - ruficanda in dense second growth scrub 5-6 feet tall + humeralis in trees. This larger is downy to short grass. Parts almost impenetrable. While killing a wounded ruficanda the bird squeaked which was immediately followed by a humeralis arriving from further up the hill. As I tried to get a shot it flew back uphill. Not sure of song as yet. Chatter usually done by two birds - often perched close together. Sometimes 3 birds are together with 2 close to each other. Not sure if all 3 are chattering.