LLW815 1963 Pirophila sumichrasti August 14 - 3 mi. E. Tehuantepec, Oaxaca chattering this morning from perches above shrub canopy. When I see them chattering the pair is usually within one or two feet of each other. Can hear single birds chattering when seen they are alone or at least other bird is not visible. 0650 - watched this same pair & both birds worked downard to ground. both use horizontal to only vertical perches on descent. Lost them when on ground but both flushed from nearly spot I had seen them disappear after about 1 minute. 0857 - sounded like chatter next giving but birds 10-12 feet apart. cannot see either bird but sound was coming from 2 directions in front of me. 0853 - softer versions of chatter heard. Perhaps this is what people are calling "whisper song". 0857 - pair came in when I schussed & sat quietly. One followed other, flew to another dead, horizontal limb 4 feet up + heard no chatter. One flew as was gone as 2nd left + this time just after second left I heard soft chatter call. sounded as if given by single bird.