Tricolored Blackbird Agelaius tricolor Audubon       Field Guide IDs: NG-436; G-298; AW-pl 615; AM(III)-292 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy REEDS F I: 11-13 DAYS ALTRICIAL SHRUB 0.5- 5 feet (To 12 feet) F 3-4 (2-6) POLYGYN F: 11-14 DAYS F-M SEEDS SNAILS FOLIAGE .....GLEAN BREEDING: Freshwater marshes, croplands. 2 broods. DISPLAYS: Similar to Red-winged Blackbird, but lacks flight display. NEST: Near or over water, also in agricultural crops. Woven of sedges, grass, forbs, lined with fine grass. Built in 4 days. EGGS: Pale green, marked with browns, black. 1.1" (28 mm). DIET: Includes clams; grass and forb seeds, grain. Proportion of seeds and grain much higher in nonbreeding season. Young fed 90% insects, snails, clams. CONSERVATION: Winters in CA breeding range and adjacent agricultural areas, s to nw Mexico. Lives in enormous flocks that occ damage grain crops, esp in fields near large breeding colonies. Control measures usu entail baiting fields with poisoned grain. NOTES: Highly gregarious in all seasons. Colonies formerly numbered up to 200,000+ nests, now to 20,000, still the highest nest density of any marsh-nesting blackbird. Feeds in flocks even when breeding. STANFORD. NOTES: ESSAYS: Variation in Clutch Sizes; Polygyny; Badges; Coloniality; Sibling Species. REFERENCES: Orians, 1985; Orians and Christman, 1968; Payne, 1969; Skorupa et al., 1980.