Thomas Custer (Former Employee)
Science and Products
Filter Total Items: 185
Egg size and laying order of snowy egrets, great egrets, and black-crowned night-herons
The nesting biology of the family Ardeidae (bitterns, herons, and egrets) has been intensively studied (e.g., Owen 1960, Milstein et al. 1970, Werschkul 1979), but egg size in relation to laying order bas not received attention. The last egg laid in gull and tern clutches is generally smaller than preceding eggs (e.g., Parsons 1970, Nisbet 1978). The relative size of the final egg in a clutch de
Authors
T. W. Custer, P. C. Frederick
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 the same c
Authors
T. W. Custer, G. Pendleton, H. M. Ohlendorf
Monooxygenase activity of black-crowned night-heron (BCNH) nestlings in Virginia, the Great Lakes and San Francisco Bay
To evaluate cytochrome P-450 related parameters as biomarkers of pollutant exposure, rates of arylhydrocarbon hydroxylase (AHH), ethoxyresorufin-O-deethylase (EROD), benzyloxyROD (BROD), pentoxyROD (PROD) and ethoxycoumarinOD (ECOD) were studied in 10-day-old BCNHs (Nycticorax nycticorax). Nestlings were collected from Chincoteague National Wildlife Refuge, VA ('controls') and from polluted sites
Authors
Barnett A. Rattner, M. J. Melancon, T. W. Custer, R. L. Hothem, K. A. King, L. J. LeCaptain, J. W. Spann
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, hexachlorobenzene,
Authors
D. V. Weseloh, T. W. Custer, B. M. Braune
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) collected from
Authors
T. W. Custer, H. M. Ohlendorf
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) collected from
Authors
T. W. Custer, H. M. Ohlendorf
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 remaining egg
Authors
T. W. Custer, C. A. Mitchell
Colony nest counts and recounts: What really counts?
No abstract available.
Authors
R.M. Erwin, W.C. Scharf, T. W. Custer, C. A. Mitchell
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 collected f
Authors
T. W. Custer, C. A. Mitchell
Organochlorines and mercury in eggs of coastal terns and herons in California, USA
In San Franciso Bay, California, USA, concentrations of DDE and mercury in eggs differed among Caspian Tern, Forster's Tern, Black-crowned Night-Heron, and Snowy Egret in 1982. Geometric mean DDE concentrations were higher (P < 0.05) in Caspian Tern eggs (6.93 ppm, wet weight) than in eggs of other species (1.92-2.84 ppm). Mean mercury concentrations were significantly greater in Caspian Tern (1.2
Authors
H. M. Ohlendorf, T. W. Custer, Roy W. Lowe, M. Rigney, E. Cromartie
Organochlorine contaminants and reproductive success of black skimmers in south Texas, 1984
Ninety-four Black Skimmer (Rhynchops niger) nests on a dredged-material island colony near Laguna Vista, Texas, were fenced and monitored in 1984 from early incubation until 21 d after the last egg hatched. The daily probability of success was greater during the nestling (99.7%/d/nest) period than during the incubation (98.5%) or hatching (98.5%) periods. By contrast, the success of eggs or young
Authors
Thomas W. Custer, Christine A. Mitchell
Nesting by pomarine jaegers near Barrow, Alaska, 1971
An estimated 5.7 pairs of pomarine jaegers km -2 (14.8 mi -2) nested near Barrow, Alaska, in 1971. Hatching success of 67 eggs (34 nests) was 57%. Fledging success of 44 nestlings (26 nests) was 32%. An estimated 0.4 young survived to 25 d of age per nesting attempt. Low fledging success is explained by an abrupt decline in lemming abundance.
Authors
Thomas W. Custer, Frank A. Pitelka
Science and Products
Filter Total Items: 185
Egg size and laying order of snowy egrets, great egrets, and black-crowned night-herons
The nesting biology of the family Ardeidae (bitterns, herons, and egrets) has been intensively studied (e.g., Owen 1960, Milstein et al. 1970, Werschkul 1979), but egg size in relation to laying order bas not received attention. The last egg laid in gull and tern clutches is generally smaller than preceding eggs (e.g., Parsons 1970, Nisbet 1978). The relative size of the final egg in a clutch de
Authors
T. W. Custer, P. C. Frederick
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 the same c
Authors
T. W. Custer, G. Pendleton, H. M. Ohlendorf
Monooxygenase activity of black-crowned night-heron (BCNH) nestlings in Virginia, the Great Lakes and San Francisco Bay
To evaluate cytochrome P-450 related parameters as biomarkers of pollutant exposure, rates of arylhydrocarbon hydroxylase (AHH), ethoxyresorufin-O-deethylase (EROD), benzyloxyROD (BROD), pentoxyROD (PROD) and ethoxycoumarinOD (ECOD) were studied in 10-day-old BCNHs (Nycticorax nycticorax). Nestlings were collected from Chincoteague National Wildlife Refuge, VA ('controls') and from polluted sites
Authors
Barnett A. Rattner, M. J. Melancon, T. W. Custer, R. L. Hothem, K. A. King, L. J. LeCaptain, J. W. Spann
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, hexachlorobenzene,
Authors
D. V. Weseloh, T. W. Custer, B. M. Braune
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) collected from
Authors
T. W. Custer, H. M. Ohlendorf
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) collected from
Authors
T. W. Custer, H. M. Ohlendorf
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 remaining egg
Authors
T. W. Custer, C. A. Mitchell
Colony nest counts and recounts: What really counts?
No abstract available.
Authors
R.M. Erwin, W.C. Scharf, T. W. Custer, C. A. Mitchell
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 collected f
Authors
T. W. Custer, C. A. Mitchell
Organochlorines and mercury in eggs of coastal terns and herons in California, USA
In San Franciso Bay, California, USA, concentrations of DDE and mercury in eggs differed among Caspian Tern, Forster's Tern, Black-crowned Night-Heron, and Snowy Egret in 1982. Geometric mean DDE concentrations were higher (P < 0.05) in Caspian Tern eggs (6.93 ppm, wet weight) than in eggs of other species (1.92-2.84 ppm). Mean mercury concentrations were significantly greater in Caspian Tern (1.2
Authors
H. M. Ohlendorf, T. W. Custer, Roy W. Lowe, M. Rigney, E. Cromartie
Organochlorine contaminants and reproductive success of black skimmers in south Texas, 1984
Ninety-four Black Skimmer (Rhynchops niger) nests on a dredged-material island colony near Laguna Vista, Texas, were fenced and monitored in 1984 from early incubation until 21 d after the last egg hatched. The daily probability of success was greater during the nestling (99.7%/d/nest) period than during the incubation (98.5%) or hatching (98.5%) periods. By contrast, the success of eggs or young
Authors
Thomas W. Custer, Christine A. Mitchell
Nesting by pomarine jaegers near Barrow, Alaska, 1971
An estimated 5.7 pairs of pomarine jaegers km -2 (14.8 mi -2) nested near Barrow, Alaska, in 1971. Hatching success of 67 eggs (34 nests) was 57%. Fledging success of 44 nestlings (26 nests) was 32%. An estimated 0.4 young survived to 25 d of age per nesting attempt. Low fledging success is explained by an abrupt decline in lemming abundance.
Authors
Thomas W. Custer, Frank A. Pitelka