Allen's Hummingbird Supersp #24 Selasphorus sasin Lesson      Field Guide IDs: NG-270; G-188; PW-pl 39; AW-pl 392; AM(II)-212 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 17-22 DAYS ALTRICIAL SHRUB VINE 1 foot - 20 feet (To 90 feet) F 2 PROMISC? F: 22-25 DAYS F INSECTS HAWKS BREEDING: Chaparral, thickets, brushy slopes, open coniferous forest. 2 broods. DISPLAYS: Male flies before female in J-shaped pattern, swooping down from a height of 75', making a prolonged metallic buzz at the bottom, then curving upward ca. 25' and hovering. Oft preceded and followed by pendulum like rocking display covering ca. 25'. NEST: Often on limb of conif or decid tree; of moss, forb stems, plant down, covered with lichen, bound with spider's silk, lined with plant down. Lichens continue to be added to exterior during incubation. Built in 8-11 days. EGGS: White, unmarked. 0.5" (13 mm). DIET: Includes spiders. CONSERVATION: Winters in Baja and c Mexico. NOTES: Nests often clustered, appearing semicolonial. Pugnacious defender of nest area. Adult males depart breeding grounds half a month before females; young males are last to leave, departing one month after adult males. STANFORD. NOTES: Uncommon spring migrant, seldom seen in summer or fall. Breeds in the adjacent foothills and possibly on campus, although nesting has not been recorded here. Most often observed foraging at feeders or flowering trees, especially eucalyptus. ESSAYS: Hummingbird Foraging Bouts; Optimally Foraging Hummers; Hummingbirds, Nectar, and Water; Coevolution; Hovering Flight; Migration; Promiscuity REFERENCES: Johnsgard, 1983; Phillips, 1975; Tyrell and Tyrell, 1984