Yellow-rumped Warbler Setophaga coronata Linnaeus       Field Guide IDs: NG-372; G-278; PE-234; PW-pl 50; AE-pl 379; AW-pl 414; AM(III)-134 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 12-13 DAYS ALTRICIAL 4 feet - 50 feet F 4-5 (3-5) MONOG F: 10-12 DAYS MF (?) BERRIES HAWKS HOVER & GLEAN BREEDING: Conif and conif-decid forests. Often 2 broods. DISPLAYS: Courting male follows female, fluffs side feathers, raises wings, erects crown feathers, calls, and flutters. NEST: Usu on horizontal branch; of shredded bark, weed stalks, twigs, rootlets, some lined with feathers interwoven so tips curve over and screen eggs, other linings including hair. EGGS: White to creamy, marked with browns, grays, occ wreathed. 0.7" (18 mm). DIET: Tends to be more insectivorous in w than in e; berries of shrubs, esp in winter. CONSERVATION: Some sedentary in winter, some s to C.A. Common (e) or rare (w) cowbird host; female may destroy cowbird eggs by burying in base of nest. NOTES: One of the most generalized and opportunistic of all our insectivorous birds. Gregarious, often assoc in flocks. Males tend to forage higher than females. May skim swallow-like over water eating insects from surface. One of last warblers to migrate. Most abundant wood warbler in Canada. Occ roost communally in winter. Until recently, e and w populations were considered separate species, Myrtle (e) and Audubon's (w) Warblers. STANFORD. NOTES: Common migrant and winter resident in various habitat types throughout campus. Densities may be quite high at flowering eucalyptus trees. ESSAYS: Taxonomy and Nomenclature; MacArthur's Warblers; Migration; Bird Guilds; Species and Speciation; Cowbirds REFERENCES: Harrison, 1984; Morse, 1980.