Geology topics

M. A. Byrd

Publications and source records attributed to M. A. Byrd.

2 recordsLinked to original sources

USGS1984

Organochlorine pesticide, polychlorobiphenyl, and mercury residues in bald eagle eggs – 1969-79 – And their relationships to shell thinning and reproduction

Bald eagle ( Haliaeetus leucocephalus ) eggs were collected in 14 States in 1969–79 and analyzed for organochlorine pesticides, polychlorobiphenyls, and mercury. Moderate shell thinning occurred in eggs from several areas. Eggs from the Chesapeake Bay area contained the highest residue levels of most organochlorines. DDE was detected in all eggs; other organochlorines were detected less frequently. Mercury levels were highest in eggs from Maine. Eight contaminants were significantly negatively correlated with shell thickness or reproduction at sampled breeding areas; DDE was most closely related to these factors. Production of young was near normal at breeding areas when DDE was ⩽3 ppm (wet weight); reproductive failure approached 100% for those breeding areas where DDE in eggs was >15 ppm. Five ppm DDE was associated with 10% shell thinning. The other contaminants that were associated with these factors were also highly correlated with DDE; their impact appeared minor in relation to those of DDE.

Archives of Environmental Contamination and Toxico↗

USGS1977

Mid-Atlantic coast osprey population: Present numbers, productivity, pollutant contamination, and status

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 pelaware 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.

Journal of Wildlife Management↗