Clark's Grebe Supersp #3 Aechinophorus clarkii Lawrence     Field Guide IDs: NG-20; P-34; PW-pl 1; AM (I)-46 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy MF I: 23 DAYS PRECOCIAL 4 MF 3-4 (2-7) MONOG F: 63-77 DAYS MF AQUATIC INVERTS BREEDING: : Marshes, lakes. 1 brood. DISPLAYS: Elaborate mutual displays performed by 2 or more birds in predictable sequences: "rushing," "weed dance," and "greeting" as in Western Grebe. NEST: Floating platform in shallow water as in Western Grebe. EGGS: Bluish-white, chalky, nest-stained buff/brown. 2.3" (58 mm). DIET: Mostly fish, aquatic inverts, few amphibians, feathers. Young fed adults' feathers. CONSERVATION: Winters s to c Mexico. Blue List 1973-82, Special Concern 1986. Plume hunters devastated populations. NOTES: Colonies of tens to hundreds of nests; gregarious year-round. Recently split into two species (Clark's and Western; Clark's is the light-faced form); single-note advertising call prevents hybridization. Tend to feed farther from shore than Western Grebe, suggesting possibility of reduced foraging overlap. Range overlaps widely with Western Grebe but rare among n populations. Bare skin patch on head of young flushes dark red when begging or in distress. Chicks carried and fed on adults' backs. STANFORD. NOTES: ESSAYS: Eating Feathers; Visual Displays; Transporting Young; Plume Trade; Species and Speciation; Blue List. REFERENCES: American Ornithologists' Union, 1985; Nuechterlein, 1981b; Storer and Nuechterlein, 1985.