Thomas Custer (Former Employee)
Science and Products
Filter Total Items: 166
Within- and among-clutch variation of organochlorine residues in eggs of black-crowned night-herons Within- and among-clutch variation of organochlorine residues in eggs of black-crowned night-herons
Within-clutch variability of DDE and PCB residues in eggs from 62 clutches of black-crowned night-herons (Nycticorax nycticorax) was small (12% and 17%) compared to among-clutch variability (88% and 83%). Significant correlations between concentrations of DDE (median r=0.8885) and of PCBs (median r=0.8244) occurred when 501 correlations were run on two randomly selected eggs from within...
Authors
T. W. Custer, G. Pendleton, H. M. Ohlendorf
Organochlorine contaminants in eggs of common terns from the Canadian Great Lakes, 1981 Organochlorine contaminants in eggs of common terns from the Canadian Great Lakes, 1981
To determine if contaminant levels in Common Terns had changed over the last decade, we collected and analyzed eggs from four nesting colonies on the three lower Great Lakes during 1981. DDE and PCBs were detected in every egg from the four colonies. Dieldrin, mirex and trans-nonachlor were detected in more than 45% of the eggs. Seven other organochlorine contaminants (DDD, DDT...
Authors
D. V. Weseloh, T. W. Custer, B. M. Braune
Brain cholinesterase activity of nestling great egrets, snowy egrets, and black-crowned night-herons Brain cholinesterase activity of nestling great egrets, snowy egrets, and black-crowned night-herons
Inhibition of brain cholinesterase (ChE) activity in birds is often used to diagnose exposure or death from organophosphorus or carbmate pesticides. Brain ChE activity in the young of altricial species increase with age; however, this relationship has only been demonstrated in the European starling (Sturnus vulgaris). Brain ChE activity of nestling great egrets (Casmerodius albus)...
Authors
T. W. Custer, H. M. Ohlendorf
Organochlorine contaminants in white-faced ibis eggs in southern Texas Organochlorine contaminants in white-faced ibis eggs in southern Texas
White-faced ibis eggs collected from 2 colonies in southern Texas in 1985 had low mean concentrations of DDE. DDD, the only other organochlorine contaminant detected, was found in only 1 of 20 eggs. DDE concentrations in eggs were not significantly correlated with eggshell thickness. Mean DDE concentrations were significantly higher in eggs collected from nests where not all of the...
Authors
T. W. Custer, C. A. Mitchell
Brain cholinesterase activity of nestling great egrets snowy egrets and black-crowned night-herons Brain cholinesterase activity of nestling great egrets snowy egrets and black-crowned night-herons
Inhibition of brain cholinesterase (ChE) activity in birds is often used to diagnose exposure or death from organophosphorus or carbamate pesticides. Brain ChE activity in the young of altricial species increases with age; however, this relationship has only been demonstrated in the European starling (Sturnus vulgaris). Brain ChE activity of nestling great egrets (Casmerodius albus)...
Authors
T. W. Custer, H. M. Ohlendorf
Organochlorine contaminants in white-faced ibis eggs in southern Texas Organochlorine contaminants in white-faced ibis eggs in southern Texas
White-faced Ibis (Plegadis chihi) eggs collected from two colonies in southern Texas in 1985 had low mean concentrations of DDE (0.14-0.27 ppm wet weight). DDD, the only other organochlorine contaminant detected, was found in only 1 of 20 eggs. DDE concentrations in eggs were not significantly correlated with eggshell thickness. Mean DDE concentrations were significantly higher in eggs...
Authors
T. W. Custer, C. A. Mitchell
Science and Products
Filter Total Items: 166
Within- and among-clutch variation of organochlorine residues in eggs of black-crowned night-herons Within- and among-clutch variation of organochlorine residues in eggs of black-crowned night-herons
Within-clutch variability of DDE and PCB residues in eggs from 62 clutches of black-crowned night-herons (Nycticorax nycticorax) was small (12% and 17%) compared to among-clutch variability (88% and 83%). Significant correlations between concentrations of DDE (median r=0.8885) and of PCBs (median r=0.8244) occurred when 501 correlations were run on two randomly selected eggs from within...
Authors
T. W. Custer, G. Pendleton, H. M. Ohlendorf
Organochlorine contaminants in eggs of common terns from the Canadian Great Lakes, 1981 Organochlorine contaminants in eggs of common terns from the Canadian Great Lakes, 1981
To determine if contaminant levels in Common Terns had changed over the last decade, we collected and analyzed eggs from four nesting colonies on the three lower Great Lakes during 1981. DDE and PCBs were detected in every egg from the four colonies. Dieldrin, mirex and trans-nonachlor were detected in more than 45% of the eggs. Seven other organochlorine contaminants (DDD, DDT...
Authors
D. V. Weseloh, T. W. Custer, B. M. Braune
Brain cholinesterase activity of nestling great egrets, snowy egrets, and black-crowned night-herons Brain cholinesterase activity of nestling great egrets, snowy egrets, and black-crowned night-herons
Inhibition of brain cholinesterase (ChE) activity in birds is often used to diagnose exposure or death from organophosphorus or carbmate pesticides. Brain ChE activity in the young of altricial species increase with age; however, this relationship has only been demonstrated in the European starling (Sturnus vulgaris). Brain ChE activity of nestling great egrets (Casmerodius albus)...
Authors
T. W. Custer, H. M. Ohlendorf
Organochlorine contaminants in white-faced ibis eggs in southern Texas Organochlorine contaminants in white-faced ibis eggs in southern Texas
White-faced ibis eggs collected from 2 colonies in southern Texas in 1985 had low mean concentrations of DDE. DDD, the only other organochlorine contaminant detected, was found in only 1 of 20 eggs. DDE concentrations in eggs were not significantly correlated with eggshell thickness. Mean DDE concentrations were significantly higher in eggs collected from nests where not all of the...
Authors
T. W. Custer, C. A. Mitchell
Brain cholinesterase activity of nestling great egrets snowy egrets and black-crowned night-herons Brain cholinesterase activity of nestling great egrets snowy egrets and black-crowned night-herons
Inhibition of brain cholinesterase (ChE) activity in birds is often used to diagnose exposure or death from organophosphorus or carbamate pesticides. Brain ChE activity in the young of altricial species increases with age; however, this relationship has only been demonstrated in the European starling (Sturnus vulgaris). Brain ChE activity of nestling great egrets (Casmerodius albus)...
Authors
T. W. Custer, H. M. Ohlendorf
Organochlorine contaminants in white-faced ibis eggs in southern Texas Organochlorine contaminants in white-faced ibis eggs in southern Texas
White-faced Ibis (Plegadis chihi) eggs collected from two colonies in southern Texas in 1985 had low mean concentrations of DDE (0.14-0.27 ppm wet weight). DDD, the only other organochlorine contaminant detected, was found in only 1 of 20 eggs. DDE concentrations in eggs were not significantly correlated with eggshell thickness. Mean DDE concentrations were significantly higher in eggs...
Authors
T. W. Custer, C. A. Mitchell