Double-crested Cormorant Supersp #4 Phalacrocorax auritus Lesson       Field Guide IDs: NG-54; G-36; PE-40; PW-pl 17; AE-p1 99; AW-pl 76; AM (I)-94 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy MF I: 25-29 DAYS ALTRICIAL TREE 6-150 feet MF 3-4 (2-7) MONOG F: 35-42 DAYS MF AQUATIC .....INVERTS SURFACE .....DIPS BREEDING: Lakes, rivers, swamps, seacoasts, along coastal cliffs. 1 brood. DISPLAYS: Complex courtship-males pursue females, splash forcefully with both wings, swim rapidly in zigzag until heads submerged, dive and surface holding veg which male drops near female or tosses in air. NEST: On tree or ground, but not both in same colony; platform of sticks, seaweed, and other drift material. Usu lined with finer materials. Stick and twig tree nests may have green leaves. EGGS: Light blue/bluish-white, usu nest-stained. 2.4" (61 mm). DIET: Primarily schooling fish; rarely other small vertebrates. Young fed regurgitant, first dripped from bill, then offered in tureenlike bill. CONSERVATION: Winters s to w c Mexico, Bahamas and Greater Antilles. Blue List 1972-81, Special Concern 1982, Local Concern 1986; populations appear to be increasing. NOTES: Usu colonial; within colonies, earliest breeders usu older, experienced nesters. Young hatch asynchronously. Young brooded almost continuously for 12 days; can maintain body temperature at 14-15 days. Eyes adapted for aerial as well as underwater vision. Energetic, aggressive defense of eggs and young from avian predators (esp Northwestern Crow, Glaucous-winged Gull). Regurgitates pellets. Vandalized colonies are abandoned. STANFORD. NOTES: ESSAYS: Incubation Time; Blue List; Pellets; Coloniality. REFERENCES: Dunn, 1976; McNeil and Leger, 1987; Siegel-Causey and Hunt, 1981; Vermeer and Rankin, 1984.