H.Wolf 1964 Selasphorus platycercus August 11 2 mi. N. Tres Cumbres, 9100 ft., Morales, Mexico This is the common humming in the pine bunchgrass association. One adult S has center of activity at edge of flowering patch of Lupinus & Pentstemon. Have seen several dive displays. Works by stages - goes 10+ feet and hovers then another 10+ feet to height of 75 to /60 feet then nearly straight down with sharp arc at bottom. Usually has 333-333-333 call at bottom of arc. There climbs again in short spurts usually to height of 25-30 feet but more rarely to same to initial height dives again - shorter dive gives more open arc. Then climbs again to full height. Aug 3-9 dives in a sequence. Only time have seen another humming at bottom of dive it was a ? Broad-tail fucking at Pentstemon. Bottom of dive closely corresponded with her position, it was 2-3 feet above tops of grass. Have seen this S chase other Broad-tails not sure of sex. Once was foreing at Pantstemon when a Colibri thalassinus approached. S Broad-tail immediately left and went back to perch 30-40 yds away. Colibri feeds freely in this Pentstemon patch but no other Broad-tails.