LLW016 1964 Aimophila viridescens August 9 5 mi. E. Cuernavaca, 5700+ft, Morelos, Mexico. Young / Marground to height of 25 feet in tangle of shrub branches. Chirping. When I approached flew 16yds. in arc + landed on tree branch 4' high. Then flew 20+yds. farther + I lost track of it. ? still chirping - this time from tree branches 6-8'ft up. Probably because it was actively chasing young. While chirping with young hidden & (+8' in 1st shrub) worked close to young. At 2nd location ? spent 50%+ of her time within 5+ feet of young. Left the pair at 7000. forage / 10:35- flushed pair + from an ground in shaded area under beet sheath cove, but beneath layer of 6-8" weeds. Both flew up into nearby trees. On walked to NE while other went to SW. one flew SW then DNW to approach other - both 8+ feet up in trees & moving along horizontal limbs. one there flew to NW to edge of shrub thicket giving chase as it went, other did not follow + I lost track of both. sing / 10:57-11:10 - ?♂ 1 singing from shaded tree grove. began singing after 3 yrs short burst of song. ?♂ 1 sang from 1 to 2+ minute. mostly -- song. once moved 10yds to E. + landed 8'ft up in lower branches of tree. then did flips landing once in dropping straight down to ground within 10 sec. he was back up to lower branches + moved back to where was singing + resumed singing. soft & loud songs / 11:25-11:40 - ?♂ 5 of ?♂ 1 singing with occasional songs by ?♂ 1. alternate type A & B songs. As in upper 1/3 of 30 foot tree + moving about as I approach. moves to back side of tree & stays there hidden from view. ♀ seems to have few soft songs followed by some loud songs. All given from same position. may relate to singing of ?♂ 1, but not obviously -