Mid-Atlantic Coast Osprey Population: Present Numbers, Productivity, Pollutant Contamination, and Status

Abstract

An estimated 233 16 (95% C.I.) pairs of ospreys (Pandion haliaetus) nested in coastal New Jersey, Delaware, Maryland, and Virginia in 1975. The present populations were considerably smaller than those reported for selected locations at the turn of the century in these four states. The New Jersey population has continued to decline during the last 25 years, although it showed some signs of improved production in 1974-75. The insecticide DDT was used intensively in New Jersey for mosquito control from about 1946 until 1966; its use in the other states was much less intensive, and of shorter duration. In a segment of the Delaware population of ospreys, production was normal and numbers increased slightly in 1970-75. Fragmentary information from Maryland suggests that the number of pairs nesting on duck blinds was about the same in 1958 and 1975. The population in coastal Virginia north of Cape Henry increased from 1970 to 1975. DDE residues in osprey eggs were highest in the areas showing the greatest population declines and the lowest production rates. J. WILDL. MANAGE. 41(2):254-265 Reduced productivity and sharp declines in osprey populations were first reported for the Connecticut River colony (Ames and Mersereau 1964). In 1964-75, populations of nesting ospreys were studied in at least 19 states, 3 provinces in Canada, and Mexico. In reviewing the North American osprey populations, Henny (1977) stated, Improvement [in production] in affected populations, mainly those along the Atlantic Coast and in the Great Lakes region, began in the late 1960s and is continuing in the 1970s. . . . Although some of the most severely affected populations are still not producing at normal rates, the pattern of improvement and an increase in management activities, including provision of nesting platforms and establishment of osprey management zones, allow cautious optimism about the future of the species in North America. He believed the recent improvement in production was due to the reduced use of DDT and other persistent pollutants. Published quantitative information from much of the area included in this study is sparse. Furthermore, our mid-Atlantic Coast study area lies between Connecticut and Long Island to the north, a region which showed extremely poor production and population declines in the 1960's and early 1970's (Ames and Mersereau 1964, Puleston 1975), and the coastal Carolinas to the south, where production has been normal and population numbers have remained unchanged (Henny and Noltemeier 1975). We review here the information on osprey populations within the mid-Atlantic region, and attempt to put into perspective the distribution and abundance of nesting ospreys in 1975. This is the third year of aerial surveys along the Atlantic Coast, which began with Chesapeake Bay in 1973 (Henny et al. 1974) and extended to coastal North and South Carolina in 1974 (Henny and 1 Present address: Patuxent Wildlife Research Center, 480 S.W. Airport Road, Corvallis, Oregon 97330. 254 J. Wildl. Manage. 41(2):1977 This content downloaded from 157.55.39.92 on Wed, 22 Jun 2016 05:11:56 UTC All use subject to http://about.jstor.org/terms MID-ATLANTIC COASTAL OSPREYS Henny et al. 255 Noltemeier 1975). E. L. Ferguson was the pilot for the present survey and J. W. Via provided unpublished data from coastal Virginia. We thank them for their cooperation and assistance.