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Erwin E. Klaas

Publications and source records attributed to Erwin E. Klaas.

25 records · Page 2Linked to original sources
USGS1978

Organochlorine residues and eggshell thinning in wood storks and anhingas

All 10 Wood Stork eggs collected at Merritt Island National Wildlife Refuge in 1973 contained residues of DDE (geometric mean 4.0 ppm wet weight) and PCBs (1.2 ppm). Nine other organochlorines were found at lower frequencies in the eggs. Eggshells from the recent period were 8.9% thinner (P < 0.001) than pre-1947 samples; decrease in eggshell thickness was more closely correlated with DDE than other organochlorines and correlation of DDE and eggshell thickness approached significance (P = 0.115).....Anhinga eggs were collected at 7 localities; 45 of the 46 eggs analyzed contained DDE residues and 24 contained PCBs. Residues of other organochlorines were found less frequently. Shell thickness of recent eggs from Louisiana and Mississippi was significantly less (-7.5%; P < 0.05) than the mean for pre-1947 eggs, but there was no significant change in shell thickness of eggs from Florida. The change in clutch mean eggshell thickness was significantly negatively correlated (P < 0.05) with the concentration of DDE in the eggs.

The Wilson Bulletin↗
USGS1977

Organochlorine pesticide and polychlorinated biphenyl residues in selected fauna from a New Jersey salt marsh--1967 vs. 1973

More than a half million pounds of DDT were applied to control mosquitoes in salt marsh estuaries of Cape May County, New Jersey, from 1946 to 1966. The use of DDT was discontinued in the County after 1966. In 1967, mean concentrations of DDT and metabolites ranged from 0.63 to 9.05 ppm in aquatic fauna, but by 1973 mean residue levels had decreased 84 to 99 percent among nine species. DDE was still present at reduced levels in nearly all samples in 1973, but other DDT isomers had mostly disappeared. Dieldrin was detected only in clapper rails, and residue levels decreased during the period. Mean concentrations of PCB's increased in the clapper rail, remained the same in the fiddler crab and mud snail, and decreased in the sheepshead minnow, mummichog, striped killifish, and salt marsh snail. Small amounts of mirex, toxaphene, cis-chlordane (and/or trans-nonachlor), oxychlordane, and HCB were detected in a few specimens.

Pesticides Monitoring Journal↗
USGS1976

Mercury in eggs of aquatic birds, Lake St. Clair-1973

Eggs from four species of aquatic birds inhabiting waterways of the Lake St. Clair region were collected in 1973 and analyzed for mercury. Species analyzed were mallard ducks (Anas platyrhynchos), common terns (Sterna hirundo), black-crowned night herons (Nycticorax nycticorax), and great egrets (Casmerodius albus). Mallard eggs contained relatively low residue levels, less than 0.05-0.26 ppm, and common tern eggs contained the highest residues, ranging up to 1.31 ppm. Mercury levels in the eggs were appreciably lower than those in the same species in 1970. The declines are attributed to the 1970 restrictions placed on industrial discharges of mercury into the St. Clair and Detroit Rivers.

Pesticides Monitoring Journal↗
USGS1976

Chemical residue content and hatchability of screech owl eggs

Eggs of wild Screech Owls were collected from nests in northwestern Ohio in 1973. One egg was taken from each of 19 nests near the start of incubation. Mean shell thickness in these 19 eggs and mean thickness of 16 unhatched eggs did not differ from 49 archival eggs collected in Ohio and Pennsylvania prior to the widespread use of organochlorine pesticides. Residues were generally low although all eggs contained DDE and PCB?s. No relationship was found between hatching failures and the presence of organochlorine residues. Low residues are consistent with a long history of good nesting success and a stable population.

The Wilson Bulletin↗
USGS1974

Avian eggshell thickness: Variability and sampling

Measurements of shell thickness of the eggs of five species were subjected to nested analyses of variance. The analyses separated variation into two or three levels for which variances and percentages of the total variation were derived. The results show that differences among measurements of the same egg contribute little to the sample variance whereas differences among eggs within clutches contribute nearly as much as differences among clutches. It is more efficient and less costly to collect entire clutches of eggs in most studies of shell thickness. Using entire clutches, sample sizes needed to detect differences of 10 percent in shell thickness (at given significance levels and power) were estimated to be eight to 11 clutches for the species studied. For differences of five percent, 26 to 38 clutches are required. Guidelines are presented which may assist other workers in evaluating the efficiency of their sampling designs, and in estimating sample sizes for detecting differences in eggshell thickness in wild birds.

The Wilson Bulletin↗