Osprey Pandion haliaetus Linnaeus       Field Guide IDs: NG-102; G-78; PW-158; PW-pl 20; AE-pl 306; AW-pl 304; AM(I)-216 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F -M I: 32-43 DAYS SEMIALTRICIAL 1 10 feet - 60 feet (0 - 200 feet) CLIFF MF 3 (2-4) MONOG F: 48-59 DAYS MF BREEDING: Along rivers, lakes, and coasts. 1 brood. DISPLAYS: Courting pair in swift pursuit flight, soar, circle, dodge with rapid turns and quick swoops. NEST: In deciduous or coniferous tree (dead or alive), near or over water, also atop pole. Of sticks, sod, cow dung, seaweed, rubbish, etc. Perennial, becoming very large. EGGS: White/pinkish-white/pinkish-cinnamon, marked with brown/olive, rarely unmarked. 2.4" (61 mm). DIET: Usu hovers at 30'- 100' and dives, mostly for fish (live or dead); also takes rodents, birds, small vertebrates, crustaceans. Young fed regurgitant first 10 days. Brood of 3 requires 6 lb of fish daily. CONSERVATION: Winters s to Chile, n Argentina. Blue List 1972-81, Special Concern 1982, Local Concern 1986; populations crashed (esp in e) 1950s-1970s from exposure to DDT, encroachment onto breeding grounds, and shooting. Coastal populations now recovered aided by DDT ban and conservation programs including successful use of artificial nesting platforms. NOTES: Female fed entirely by mate from pair formation through egg laying; courtship feeding may ensure mate fidelity. Male occ does up to 30% of incubation. Male delivers food to female at nest; she then feeds young. Female does most of brooding. Young hatch asynchronously. Subject to piracy by Bald Eagle, frigatebird. Only raptor whose front talons turn backward. STANFORD. NOTES: ESSAYS: DDT; Feet; Raptor Hunting; Conservation; Blue List; Poisons; Courtship Feeding. REFERENCES: Cramp and Simmons, 1980; Levenson, 1979; Poole, 1985; Reese, 1977; Van Daele and Van Daele, 1982.