Basic Information
Common Name: Osprey
Scientific Name: Pandion haliaetus
Species Code:
Management Category: VG (species not specifically managed for, but may benefit from vegetation management for VF species)
Occurrence Map
Table of Occurrences
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Current Distribution Rangewide

Worldwide distribution; In the United States breeding populations occur along the Pacific Coast, in the Western Interior, the Great Lakes, the Atlantic Coast , Alaska, Florida, and the Gulf Coast. Winters from southern North America south to Central America and South America [1]. Pacific Coast populations extend from Washington to southern California, including the Channel Islands.

Known Populations in San Diego County

Occurs in MUs 1, 2, 3, 4, 6, and 7 in the MSPA, with most known localities along the coast and in the coastal lowland [2]. Also found further inland at Lakes Cuyamaca, Barrett, and Moreno.

List Status

Not listed

Habitat Affinities

Exposed locations are needed for construction of their large nests. Often found on pillars of rock in the surf, on over-hanging ledges close above the water, and tops of older trees or artificial substrates that are located within 500 meters of open water [3]. Known to nest in a diversity of habitats as long as fishable waters are accessible [4].

Taxonomy and Genetics

Four recognized subspecies differentiated by geographic distribution, size and coloration. Only one subspecies, Pandion haliateus carolinensis is found in North America [5].

Seasonal Activity

Yearlong, diurnal activity. Nesting season begins mid-March to early April. Fall migration begins in October heading south along coast and western slope of Sierra Nevada to Central and South America. In the winter the osprey occurs more frequently than in breeding season [6].

Life History/Reproduction

Breeds March to September. Clutch size 1-4 eggs, usually 3. Colonial nesting is common. Young breed first at 3 yr. Pesticides caused reproductive failure in past, but reproductive success has increased since the banning of nondegradable organochlorine pesticides in the early 1970's [7, 8].

Diet and Foraging

Primarily consumes fish; forages over fishable waters diving up to a meter in depth for prey [9]. Occasionally takes small mammals, birds, reptiles, amphibians, and invertebrates.

Dispersal

Home ranges vary with season and quality of habitat; during breeding season travels up to 8-10 km from nests to forage for fish, mainly near the coast [10].

Threats

Threatened by exposure to mercury and other contaminants in the food chain. Vulnerable to power line and pole electrocutions, direct mortality with wind turbines, collisions with vehicles, overfishing, and urbanization [11, 12, 13].

Special Considerations:

Populations in North America have stabilized or increased with the restriction or banning of certain pesticides. Use of poles that support electrical lines have posed risks of electrocution, power outages, and fires. Recommendations to modify these nest that occur on poles has been accomplished in many countries. Ospreys are surprisingly tolerant of human activity and nest in urban and suburban habitats. Habituation is imperative for this species and pairs that are not used to human activity may abandon nests if disturbance is sudden or for extended duration [14].

Literature Sources

[1] Henny, Charles J. "Distribution and abundance of nesting ospreys in the United States." Biology and management of bald eagles and ospreys. Harpell Press, Ste. Anne de Bellevue, Quebec 325 (1983): 175-186.

[2] Unitt, Philip. San Diego County bird atlas. San Diego: San Diego Natural History Museum, 2004.

[3] Ewins, Peter J."Osprey (Pandion Haliaetus) Populations in Forested Areas of North America: Changes, Their Causes and. "J Raptor Res 31.2 (1997): 138-150.

[4] Bent, A.C. 1937. Life histories of North American birds of prey, (Part 1). United States National Museum Bulletin 167. Washington, DC U.S.A.

[5] Bierregaard, R.O., Jr., A. Ben David, L. Gibson, R.S. Kennedy, A.F. Poole, M.S. Scheibel, and J. Victoria. 2014. Post-DDT recovery of Osprey (Pandion haliaetus) populations in southern New England and Long Island, New York, 1970–2013. Journal of Raptor Research 48:361–374.

[6] Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California's Wildlife. Vol. I-III. California Depart. of Fish and Game, Sacramento, California

[7] Garber, D. P. 1972. Osprey study, Lassen and Plumas counties, California, 1970-71. Calif. Dep. Fish and Game, Sacramento. Wild. Manage. Br. Admin. Rep. 72-1. 33pp.

[8] Airola, D. A., and N. Shubert. 1981. Reproductive success, nest site selection, and management of ospreys at Lake Almanor, California. Cal-Neva Wildlife Trans. 1981:79-85.

[9] Maccarter, D. S. 1972. Food habits of Osprey at Flathead Lake, Montana. Unpublished M.S. Thesis, Arcata, California, Humboldt State Univ.

[10] French, J. M., and J. R. Koplin. 1977. Distribution, abundance, and breeding status of ospreys in northwestern California. Pages 223-240 in J. C.Ogden, ed. north American Osprey Research Conf. U.S. Natl. Park Serv. Trans. and Proc. Series 2. 258pp.

[11] Lounsbury-Billie, M.J., G.M. Rand, Y. Cai, and O.L. Bass. 2008. Metal concentrations in osprey (Pandion haliaetus) populations in the Florida Bay estuary. Ecotoxicology 17: 616-622.

[12] Barrios, L. and A. Rodriguez. 2004. Behavioral and environmental correlates of soaring-bird mortality at on-shore wind turbines. Journal of Applied Ecology 41:72–81.

[13] Orloff, S. and A. Flannery. 1992. Wind turbine effects on avian activity, habitat use, and mortality in Altamont Pass and Solano County Wind Resource Areas 1989-1991. Final report to the California Energy Commission, Sacramento

[14] Poole, Alan F.. 2009. Osprey (Pandion haliaetus), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=119196