Black-headed Grosbeak Supersp #48 Pheuclicus melanocephalus Swainson       Field Guide IDs: NG-428; G-310; PE-276; PW-pl 56; AE-pl 399; AW-pl 443; AM(III)-206 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy MF I: 12-13 DAYS ALTRICIAL SHRUB 4 feet - 12 feet F 3-4 (2-5) MONOG F: 11-12 DAYS MF SEEDS FRUIT BREEDING: Riparian woodland and thickets, edges of ponds, open woodland. 1? brood. DISPLAYS: Courting male performs song-flights above female with his wings and tail spread while singing nearly continuously, then returns to original perch. Song-flights also occur during incubation. NEST: Bulky, loosely built of twigs, plant stems, rootlets, lined with finer stems and rootlets. Built in 3-4 days. EGGS: Pale green, blue, or bluish-green, marked with browns or purples, esp at larger end. 1.0" (25 mm). DIET: Includes spiders, occ buds. CONSERVATION: Winters s through Mexico to Oaxaca and Veracruz. Uncommon cowbird host. NOTES: Both sexes occ sing on nest and are difficult to flush from nest; female songs less complex, more variable than male songs. Female very aggressive in defending territory against other Black-headed Grosbeaks. Both sexes brood. Young able to fly at ca. 15 days; may recognize parents' songs. STANFORD NOTES: Uncommon migrant in various habitats throughout campus, most common near the Dish where it breeds in small numbers in wooded areas. ESSAYS: Great Plains Hybrids; Decline of Eastern Songbirds; Bills; Territoriality REFERENCES: Kroodsma, 1974; Ritchison, 1983, 1985.