C. humilei 95 Río Guamol, 14 mi. E Naltepex, Oaxaca May 3 more than 2ft. or so above the ground. Very few other birds in the area - few Turdus grapi, many Poleiolola (black capped type), Seturn gularis & peustelatus, social flycatcher, Kipkadee - both common. T. pleurostictus, linea long, yellow warbler, small flycatcher - Empidonax, longer Myiornthus flycatcher- a small species - but larger than nuttings -, Caloitta, Now or less riparian - Cassiculus melanocerus (common), Mormotus mexicanus, Onthali vetula, grackle. Others are Amazoma allifom, Chrotophaga (common in worn habitat), pygmy owl, hooded hawk, Chlordeiles, audifannis, Nychedromus (in worn habitat). I believe the ? worn gives the trill much more often than the o?. Probably ? trills while o sings when they duet. Only heard single birds singing today - "the weet" or "wee sheet" exclusively - probably the o?. Have not heard two birds sing this to- gether but have heard one sing while other trills. When bird flies at speeds tail before landing and it is conspicuous - pairs seen to stay close when moving and sometimes posture with tail spread - usually duet in this position. Singing continues most of day but drops off around noon. Will answer imitations. Seems to be "normal" set-up with pairs evenly spaced in the habitat & working on single nests - a very different situation compared to hoomlies Chiapensis.