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Thomas W Custer - One of the best experts on this subject based on the ideXlab platform.
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perfluorinated compound concentrations in great blue Heron eggs near st paul minnesota usa in 1993 and 2010 2011
Environmental Toxicology and Chemistry, 2013Co-Authors: Thomas W Custer, Christine M Custer, Paul M Dummer, Kurunthachalam Kannan, Annette TrowbridgeAbstract:A great blue Heron (Ardea herodias) colony on Pig's Eye Island on the Mississippi River near St. Paul, Minnesota, USA, is located near several potential perfluorinated compound (PFC) sources. The PFC concentrations in great blue Heron eggs reported from a 1993 collection from the Pig's Eye colony were among the highest measured in bird eggs worldwide. The objective of this investigation was to determine whether PFC concentrations in great blue Heron eggs at the Pig's Eye colony have changed since 1993. Total PFC concentrations in great blue Heron eggs collected at the Pig's Eye colony in 2010 and 2011 (geometric mean = 340 and 492 ng/g wet wt) were 60% lower than the 1993 collection (1,015 ng/g wet wt). Among PFCs, perfluoroalkyl sulfonate concentrations were lower and perfluoroalkyl carboxylate concentrations were higher in the 2010 and 2011 collections. Two of 20 (10%) of the eggs analyzed from Pig's Eye in 2010 and 2011 were >1,000 ng PFCs/g wet weight and the maximum PFC value (2,506 ng PFCs/g wet wt) measured in 2010 and 2011 was among the highest PFC concentration reported in bird eggs. These high concentrations are at levels associated with physiological and neurological effects in birds. Environ. Toxicol. Chem. 2013;32:1077–1083. © 2013 SETAC
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Prevalence of eustrongylidosis in wading birds from colonies in California, Texas, and Rhode Island, USA
Colonial Waterbirds, 1994Co-Authors: J. Christian Franson, Thomas W CusterAbstract:-Snowy Egret (Egretta thula) and Black-crowned Night-Heron (Nycticorax nycticorax) nestlings from colonies in Texas, Rhode Island, and California and Great Egret (Casmerodius albus) nestlings from Texas were examined for eustrongylidosis, or infection by the parasitic nematode Eustrongylides spp. In 31% (24/77) of all broods examined, at least one nestling was infected. Snowy Egret broods from Texas were more frequently (100%) infected than those from California (20%) or Rhode Island (10%), and the prevalence of eustrongylidosis in 5and 10-dayold Snowy Egret nestlings was higher in the Texas colony than the other two. Within the Texas colony, the frequency of eustrongylidosis was greater for Snowy Egret (100%) and Great Egret (80%) broods than for Black-crowned Night-Heron broods (12.5%). Also in Texas, eustrongylidosis was more frequent in 5-day-old Snowy Egret nestlings than 5-day-old Black-crowned Night-Heron or Great Egret nestlings, and in 10-day-old Snowy Egret nestlings than in 10-day-old Black-crowned Night-Heron nestlings. Eustrongylides spp. caused perforations of the gastrointestinal tract and peritonitis, particularly in Snowy Egrets. Received 9June 1994, accepted 10 September 1994.
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Prevalence of eustrongylidosis in wading birds from colonies in California, Texas, and Rhode Island, USA
Colonial Waterbirds, 1994Co-Authors: J. Christian Franson, Thomas W CusterAbstract:-Snowy Egret (Egretta thula) and Black-crowned Night-Heron (Nycticorax nycticorax) nestlings from colonies in Texas, Rhode Island, and California and Great Egret (Casmerodius albus) nestlings from Texas were examined for eustrongylidosis, or infection by the parasitic nematode Eustrongylides spp. In 31% (24/77) of all broods examined, at least one nestling was infected. Snowy Egret broods from Texas were more frequently (100%) infected than those from California (20%) or Rhode Island (10%), and the prevalence of eustrongylidosis in 5and 10-dayold Snowy Egret nestlings was higher in the Texas colony than the other two. Within the Texas colony, the frequency of eustrongylidosis was greater for Snowy Egret (100%) and Great Egret (80%) broods than for Black-crowned Night-Heron broods (12.5%). Also in Texas, eustrongylidosis was more frequent in 5-day-old Snowy Egret nestlings than 5-day-old Black-crowned Night-Heron or Great Egret nestlings, and in 10-day-old Snowy Egret nestlings than in 10-day-old Black-crowned Night-Heron nestlings. Eustrongylides spp. caused perforations of the gastrointestinal tract and peritonitis, particularly in Snowy Egrets. Received 9June 1994, accepted 10 September 1994.
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Growth rates of great egret, snowy egret and black-crowned night-Heron chicks
Colonial Waterbirds, 1991Co-Authors: Thomas W Custer, D. W. PetersonAbstract:-Growth rates of Great Egret (Casmerodius albus), Snowy Egret (Egretta thula), and Black-crowned Night-Heron (Nycticorax nycticorax) chicks to 18 days-of-age were estimated from repeated measurements of chicks in broods of three young. Weight gain (g/day) or increase in length (mm/day) of forearm, tarsus, or culmen did not differ between Black-crowned Night-Heron chicks at a colony in Rhode Island and a colony in Texas. In Black-crowned Night-Herons and Great Egrets, the last chick (C-chick) to hatch had lower growth rates than the first (A-) or second (B-) hatched chick. Black-crowned Night-Heron and Great Egret A-chicks gained weight faster than Snowy Egret A-chicks; however, growth rates of the forearm, tarsus, or culmen each were not different among the three species. Equations based on the growth rate of culmen, forearm, or tarsus for repeatedly measured A-chicks estimated age of Great Egret, Snowy Egret, and Black-crowned Night-Heron chicks collected elsewhere to within two days of known age. Received 16 November 1990, accepted 25 February 1991.
Monique Boily - One of the best experts on this subject based on the ideXlab platform.
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Contamination and Biomarkers in the Great Blue Heron, an Indicator of the State of the St. Lawrence River
Ecotoxicology, 2006Co-Authors: Louise Champoux, Monique Boily, Suzanne Trudeau, Jean Rodrigue, Philip A. Spear, Alice HontelaAbstract:In 1996–1997, nine breeding colonies of the great blue Heron on the St. Lawrence River and its estuary (Québec, Canada) were investigated in the framework of a biomonitoring program. Fledglings from colonies in freshwater were more contaminated with mercury, PCBs and many organic contaminants than those from estuarine colonies. The level of contamination in the St. Lawrence River is generally below the levels of toxicological effects for the great blue Heron. The molar ratio of retinol: retinyl palmitate in Heron eggs was correlated with total PCBs ( r =0.79) and Mirex ( r =0.90). In plasma, all biochemical parameters were significantly different between freshwater and marine colonies. Plasma retinol concentrations at the Dickerson and Hérons colonies were significantly lower compared with those at Grande Ile ( p
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Assessment of Contamination and Biomarker Responses in Two Species of Herons on the St. Lawrence River
Environmental Monitoring and Assessment, 2002Co-Authors: Louise Champoux, Monique Boily, Jean-luc Desgranges, Alice Hontela, Suzanne Trudeau, Jean Rodrigue, Philip SpearAbstract:This study was undertaken to validate potential biomarkers of exposure and effects due to chemical contaminants in breedingcolonies of the Great Blue Heron and the Black-crowned Night-Heron on the St. Lawrence River. Eggs and fledglings from both species were collected from many colonies along theRiver. The fledglings from colonies in freshwater and brackishwater were more contaminated by mercury and PCBs than those from estuarine and gulf colonies. With respect to fledglings ofthe two Heron species, some morphometric and blood biochemicalmeasurements, including plasma thyroid hormones and retinol, were significantly different among colonies. Significant differences were also observed in liver retinoids, EROD and porphyrins among colonies. The results of this study suggestthat plasma retinoids and thyroid hormones are good biomarkersof exposure and effects, and are sufficiently sensitive to reflect local and regional variations in contamination. Along with the measure of contaminants in egg and plasma, they constitute non-invasive biomarkers which represent an importantcriteria for long term monitoring of wildlife species. It is concluded that the Great Blue Heron is an appropriate sentinelspecies in the surveillance network for the St. Lawrence River.
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β-carotene and retinoids in eggs of Great Blue Herons (Ardea herodias) in relation to St Lawrence River contamination
Ecotoxicology, 1994Co-Authors: Monique Boily, L. Champoux, D. H. Bourbonnais, J. L. Granges, J. Rodrigue, P. A. SpearAbstract:The potential use of retinoids and β-carotene as biomarkers in the eggs of the Great Blue Heron was investigated. In the spring of 1991, 65 eggs were collected from nine Heronries (seven along the St Lawrence River and two reference sites). A method was specifically developed for the extraction and analysis of β-carotene and the retinoids in Heron egg yolks by reversed-phase HPLC. When results were expressed either as the molar ratio of retinol: retinyl palmitate or as retinyl palmitate concentration, significant differences were found between colonies; however, retinyl palmitate concentration was deemed the better biomarker because it was not significantly influenced by embryonic stage of development. Retinyl palmitate concentrations in freshwater colonies were negatively related to PCB congeners Nos 105 and 118 as well as their TCDD-EQ values ( p < 0.02, r ^2=0.78). Egg tetrachloro-mono- ortho biphenyl concentrations were also negatively related to retinyl palmitate ( p < 0.005, r ^2=0.90). With the exception of the two mono- ortho co-planar congeners detected in the present study, the contamination levels found in Heron eggs were well below those found for other bird species in the Great Lakes area and, so far, no detrimental effects have been reported in Great Blue Heron populations in Quebec. These results suggest that retinyl palmitate may be useful as a sensitive and non-invasive biomarker for monitoring organochlorine contaminant effects in the Great Blue Heron in freshwater sites.
Alice Hontela - One of the best experts on this subject based on the ideXlab platform.
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Contamination and Biomarkers in the Great Blue Heron, an Indicator of the State of the St. Lawrence River
Ecotoxicology, 2006Co-Authors: Louise Champoux, Monique Boily, Suzanne Trudeau, Jean Rodrigue, Philip A. Spear, Alice HontelaAbstract:In 1996–1997, nine breeding colonies of the great blue Heron on the St. Lawrence River and its estuary (Québec, Canada) were investigated in the framework of a biomonitoring program. Fledglings from colonies in freshwater were more contaminated with mercury, PCBs and many organic contaminants than those from estuarine colonies. The level of contamination in the St. Lawrence River is generally below the levels of toxicological effects for the great blue Heron. The molar ratio of retinol: retinyl palmitate in Heron eggs was correlated with total PCBs ( r =0.79) and Mirex ( r =0.90). In plasma, all biochemical parameters were significantly different between freshwater and marine colonies. Plasma retinol concentrations at the Dickerson and Hérons colonies were significantly lower compared with those at Grande Ile ( p
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Assessment of Contamination and Biomarker Responses in Two Species of Herons on the St. Lawrence River
Environmental Monitoring and Assessment, 2002Co-Authors: Louise Champoux, Monique Boily, Jean-luc Desgranges, Alice Hontela, Suzanne Trudeau, Jean Rodrigue, Philip SpearAbstract:This study was undertaken to validate potential biomarkers of exposure and effects due to chemical contaminants in breedingcolonies of the Great Blue Heron and the Black-crowned Night-Heron on the St. Lawrence River. Eggs and fledglings from both species were collected from many colonies along theRiver. The fledglings from colonies in freshwater and brackishwater were more contaminated by mercury and PCBs than those from estuarine and gulf colonies. With respect to fledglings ofthe two Heron species, some morphometric and blood biochemicalmeasurements, including plasma thyroid hormones and retinol, were significantly different among colonies. Significant differences were also observed in liver retinoids, EROD and porphyrins among colonies. The results of this study suggestthat plasma retinoids and thyroid hormones are good biomarkersof exposure and effects, and are sufficiently sensitive to reflect local and regional variations in contamination. Along with the measure of contaminants in egg and plasma, they constitute non-invasive biomarkers which represent an importantcriteria for long term monitoring of wildlife species. It is concluded that the Great Blue Heron is an appropriate sentinelspecies in the surveillance network for the St. Lawrence River.
Gadi Katzir - One of the best experts on this subject based on the ideXlab platform.
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Visual fields in the Black‐crowned Night Heron Nycticorax nycticorax: nocturnality does not result in owl‐like features
Ibis, 2008Co-Authors: Gadi Katzir, Graham R. MartinAbstract:Compared with diurnally active species, the eyes of nocturnally active Herons (Ardeidae) are relatively larger and more widely separated. These features are found in comparisons between the nocturnally foraging Black-crowned Night Heron Nycticorax nycticorax and the diurnally active Cattle Egret Bubulcus ibis. Casual viewing of the Black-crowned Night Heron gives the impression of a somewhat owl-like appearance, with an apparently wide degree of binocular overlap. Visual fields and eye movements were determined in two alert, restrained Black-crowned Night Herons with the use of an ophthalmoscopic technique. A wide degree of binocular overlap was not confirmed, and the Black-crowned Night Heron's visual field closely resembles those of diurnally foraging Herons (Western Reef Heron Egretta gularis schistacea, Squacco Heron Ardeola ralloides, Cattle Egret). The Black-crowned Night Heron's binocular field is vertically long and narrow (maximum width 22d), with the bill placed approximately at the centre. Monocular and cyclopean field widths in the horizontal plane equal 171d and 320d, respectively. Retinal binocular overlap can be abolished by eye movements. There is a blind sector (10–13d wide) at the margin of each eye's optical field, and this results in the functional retinal binocular field being much narrower than the optical binocular fields. It is these blind sectors which give rise to the appearance of a much wider binocular field. The visual field characteristics of this Heron species may be best understood in relation to the foraging technique of capturing agile, evasive prey directly in the bill. The comparatively large size of the Black-crowned Night Herons' eyes may be associated with activity over a wide range of natural light levels but does not give rise to binocular fields larger than those of diurnal Heron species.
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Visual fields and eye movements in Herons (Ardeidae)
Brain behavior and evolution, 1994Co-Authors: Graham R. Martin, Gadi KatzirAbstract:The visual fields and eye movements of three Heron species (Ardeidae; Ciconiiformes): the cattle egret ( Bubulcus ibis ), the squacco Heron ( Ardeola ralloides ), the
Graham R. Martin - One of the best experts on this subject based on the ideXlab platform.
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Visual fields in the Black‐crowned Night Heron Nycticorax nycticorax: nocturnality does not result in owl‐like features
Ibis, 2008Co-Authors: Gadi Katzir, Graham R. MartinAbstract:Compared with diurnally active species, the eyes of nocturnally active Herons (Ardeidae) are relatively larger and more widely separated. These features are found in comparisons between the nocturnally foraging Black-crowned Night Heron Nycticorax nycticorax and the diurnally active Cattle Egret Bubulcus ibis. Casual viewing of the Black-crowned Night Heron gives the impression of a somewhat owl-like appearance, with an apparently wide degree of binocular overlap. Visual fields and eye movements were determined in two alert, restrained Black-crowned Night Herons with the use of an ophthalmoscopic technique. A wide degree of binocular overlap was not confirmed, and the Black-crowned Night Heron's visual field closely resembles those of diurnally foraging Herons (Western Reef Heron Egretta gularis schistacea, Squacco Heron Ardeola ralloides, Cattle Egret). The Black-crowned Night Heron's binocular field is vertically long and narrow (maximum width 22d), with the bill placed approximately at the centre. Monocular and cyclopean field widths in the horizontal plane equal 171d and 320d, respectively. Retinal binocular overlap can be abolished by eye movements. There is a blind sector (10–13d wide) at the margin of each eye's optical field, and this results in the functional retinal binocular field being much narrower than the optical binocular fields. It is these blind sectors which give rise to the appearance of a much wider binocular field. The visual field characteristics of this Heron species may be best understood in relation to the foraging technique of capturing agile, evasive prey directly in the bill. The comparatively large size of the Black-crowned Night Herons' eyes may be associated with activity over a wide range of natural light levels but does not give rise to binocular fields larger than those of diurnal Heron species.
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Visual fields and eye movements in Herons (Ardeidae)
Brain behavior and evolution, 1994Co-Authors: Graham R. Martin, Gadi KatzirAbstract:The visual fields and eye movements of three Heron species (Ardeidae; Ciconiiformes): the cattle egret ( Bubulcus ibis ), the squacco Heron ( Ardeola ralloides ), the
