LLW014 1964 5 Aimophila humeralis July 15 Cañon de lobos, 7mi E Cuernavaca, Morelos, Mexico 0845- other bird flew uphill to app. 15'+ foraged in vine tangle. then both flew to small shrub at base of 3-4' Acacia mesquite. one foraged at main stem (10°)+ into pointed portion. Other dropped into tangle at base. Both then flew 10' downhill in shrubs + Acacia mesquite. one hidden from view + other moved up + sat quietly in open. Then both into mesquite when foraging. haven't seen any attempts at capture for 15+ minutes. one or both chipping softly. kept returning to interior of same Acacia ~3 tall. seems to be same bird. Other sits on various perches around Acacia + on one branch extending horizontally 3-4 feet. 0803- (ex) active birds begins short chatter + both become more active. ?(?) back & forth to interior of Acacia while ♂(?) moves from next shrub to N to horizontal branch. Only 3-4 short chatters by one bird then soft chipping. 0809- both slightly uphill to other Acacia where ♂(?) gave single short chatter then both took downhill + one into interior of Acacia. 0811- both downhill 20± feet when chipped excitedly but softly. I moved away from my position ~20' to NEg Acacia to 10± yds. to S. Both birds returned one to nearby shrub + one to Acacia. worked around interior then to area where some grasses strewn about branches. Made settling movements + assumed horizontal position as if sitting on nest. Then got up + moved slightly. Settled back down. ♂(white in pectoral band) flew to another nearby shrub when continued to chip then became silent. ♀ finally onto nest at 0818.