Willow Flycatcher Superspecies #29 Empidonax traillii Audubon       Field Guide IDs: NG-288; G-212; PE-198; AE-pl 462; AW-pl 518; AM(Il)-258 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 12-13 DAYS ALTRICIAL DECID TREE 2 feet - 10 feet (1 foot - 18 feet) F 3-4 (2-4) MONOG F: 12-14 DAYS MF BERRIES HOVER & .......GLEAN BREEDING: Swamps and thickets esp willow. 1 brood. DISPLAYS: Courtship chase. NEST: In upright or slanting fork; compact, of bark, weed stems, grass, lined with grass, hair, plant down, feathers. Female selects nest site, accompanied by male. EGGS: Buff, occ white, spotted with browns near large end. 0.7" (18 mm). DIET: Also few seeds. CONSERVATION: Winters from s Mexico to Panama. Common cowbird host; occ bury cowbird egg in bottom of nest. Blue List 1980-82, Special Concern 1986; w coast populations apparently declining. Populations increase with reduction of cattle grazing and the cessation of poisoning and removal of riparian willows. NOTES: In contrast to typical songbirds, song is entirely innate, rather than learned or partly learned. Females also sing territorial song. Interspecifically territorial with Alder Flycatcher in BC and in ne U.S. Rare polygyny documented. Female broods young for 7-8 days. Formerly known as Traill's Flycatcher, which included Alder Flycatcher. STANFORD. NOTES: ESSAYS: Blue List; Superspecies; Vocal Development; Sibling Species; Interspecific Territoriality; Polygyny; Bills. REFERENCES: Ettinger and King, 1980; Frakes and Johnson, 1982; Kroodsma, 1984; Seutin, 1987; Taylor and Littlefield, 1986.