Geology topics

D. L. Meeker

Publications and source records attributed to D. L. Meeker.

4 recordsLinked to original sources

USGS2013

Residues in common flicker and mountain bluebird eggs one year after a DDT application

Common flicker ( Colaptes auratus ) and mountain bluebird ( Sialia currucoides ) eggs were examined 1 year after DDT application and showed a marked difference. Residue levels in mountain bluebird eggs were approximately 10 times higher than in common flicker eggs (5.29 to 0.58 ppm wet weight). These differences can be explained by disparate dietary habits. The mean level in American kestrel ( Falco sparverius) eggs collected in the spray area at the same time was 6.42 ppm wet weight.

Bulletin of Environmental Contamination and Toxico↗

USGS1981

An evaluation of blood plasma for monitoring DDE in birds of prey

Laboratory and field studies show that DDE residues in blood plasma are highly correlated with DDE in the brain, the rate of DDE exposure and the amount of DDE in eggs of free-living birds of prey. A blood sampling approach is proposed to supplement existing environmental contaminant methods available for birds of prey. Residues (ΣDDT) in plasma provide some direct information; however, a method is proposed to adjust blood plasma residues from four species of birds of prey to the estimated residues in eggs for the purpose of residue interpretation. The blood plasma-egg relationship appears to be species-independent in the four raptors studied. Two predicting equations are presented for estimating egg residues, one for plasma samples collected prior to, or within a few days of, egg laying, and another for the post-laying period. Limitations and advantages of the blood plasma monitoring approach are discussed. The approach may be particularly suitable for endangered species research.

Environmental Pollution (Series A)↗

USGS1980

White-faced ibis populations and pollutants in Texas, 1969-1976

Eggshell thickness, levels of pollutant residues, and population status of the white-faced ibis (Plegadis chihi) were monitored in Texas from 1969 through 1976. Texas ibis nesting populations declined by 42%. Reproductive success apparently was limited by DDE-induced shell thinning and by dieldrin-caused mortality. Eggshells averaged 4% to 10% thinner than the pre-1943 mean thickness. Shells of numerous crushed eggs exceeded 20% thinning. Mean DDE residues in randomly collected eggs decreased from 0.94 ppm in 1970 to 0.25 ppm in 1976. DDE was higher, averaging 2.5 ppm, in thin-shelled eggs. DDE was negatively correlated with shell thickness. Dieldrin and PCB residues increased slightly from 1970 to 1976, but neither was correlated significantly with shell thickness. Residues in brains of many dead and dying ibises collected during years of extreme reproductive failure, 1970 and 1973, contained between 5 and 25 ppm dieldrin. Ibises were exposed to aldrin and dieldrin by feeding in rice fields where aldrin-treated rice seed was planted. Improved nesting success in 1976 may have been related to declining residues of DDE and to the discontinued use of aldrin in rice fields.

Southwestern Naturalist↗

USGS1972

Pesticide mortality of young white-faced ibis in Texas

The combination of the symptoms observed in sick and dying birds and the high brain residues in the three birds collected dying, as well as in two of the four collected dead, implicate dieldrin as at least one of the causes of mortality of young ibis at the Lavaca Bay colony. Mercury residues in the kidneys of all four dead young, including those with low brain residues of dieldrin, suggest that birds were exposed to mercury in rice fields and that mercury may also have contributed to the mortality. Since adult ibis normally feed their young on invertebrates collected in rice fields treated with aldrin and Ceresan L, the use of these rice pesticides appears to be a serious hazard to this species, and probably to other wild birds with similar habits.

Texas↗