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Osprey distribution, abundance, and status in western North America: I. The northern California population

January 1, 1978

An estimated 355± 40 pairs (95 percent C.I.) of Ospreys (Pandion haliaetus carolinensis) nested in the northern California survey area in 1975. Eighty-one pairs were estimated along the extreme northern coast in Del Norte and Humboldt Counties. One hundred and forty-four pairs were estimated along California's northern coast in Mendociuo, Sonoma, and Marin Counties. The northern interior region, primarily in Siskiyou, Trinity, Shasta, Lassen, and Plumas Counties, contained an estimated 130 pairs. Forty-nine percent of the interior Osprey population is associated with reservoirs that were not present in 1900. We believe more Ospreys are present in the interior now than 75 years ago because of the increase in suitable habitat; nevertheless, populations at Shasta Lake and Clair Engle Lake are now exhibiting below-normal production rates and local declines. The long-term status of the coastal population, nesting along rivers, streams, and bays, is not clear. Recent production rates from two segments of the coastal population appear to be normal, but production at Usal Creek is below normal.

Publication Year 1978
Title Osprey distribution, abundance, and status in western North America: I. The northern California population
Authors Charles J. Henny, David J. Dunaway, Robert D. Mallette, James R. Koplin
Publication Type Article
Publication Subtype Journal Article
Series Title Northwest Science
Index ID 5220987
Record Source USGS Publications Warehouse
USGS Organization Patuxent Wildlife Research Center