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Christine A Bishop - One of the best experts on this subject based on the ideXlab platform.
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health of tree swallow Tachycineta bicolor nestlings exposed to chlorinated hydrocarbons in the st lawrence river basin part ii basal and stress plasma corticosterone concentrations
Journal of Toxicology and Environmental Health, 2003Co-Authors: Barbara Martinovic, Anne L Secord, Christine A Bishop, Erinn Birmingham, David R S Lean, Ken JockAbstract:: Sixteen-day-old tree swallows (Tachycineta bicolor) were collected in 1999 and 2000 from nine sites within the vicinity of the St. Lawrence River in Canada and the United States to determine if organochlorine contaminant concentrations correlated with corticosterone levels. Basal plasma corticosterone levels were determined in chicks reared in nest boxes, and stress plasma corticosterone levels were determined in chicks after exposure to a 10-min standardized stress test. Mean basal plasma corticosterone concentrations ranged from 4 to 37 ng/ml in 1999, and from 5 to 20 ng/ml in 2000. Mean poststress plasma corticosterone levels ranged from 26 to 67 ng/ml in 1999, and from 26 to 109 ng/ml in 2000. In 1999 and 2000, basal corticosterone was negatively correlated with polychlorinated dibenzofuran (PCDF). Total PCDFs ranged from 4.8 to 120.5 ng/kg wet weight in chicks in 1999 and 2000 among sites. These results indicate that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries may be interfering with the glucocorticoid endocrine axis of tree swallows.
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health of tree swallow Tachycineta bicolor nestlings exposed to chlorinated hydrocarbons in the st lawrence river basin part i renal and hepatic vitamin a concentrations
Journal of Toxicology and Environmental Health, 2003Co-Authors: Barbara Martinovic, Anne L Secord, Christine A Bishop, Erinn Birmingham, David R S Lean, Ken JockAbstract:Sixteen-day-old tree swallows (Tachycineta bicolor), near fledging, were collected in 1999 and 2000 from nine sites representing a gradient of dioxin concentrations, within the vicinity of the St. Lawrence River in Canada and the United States, to determine if organochlorine contaminants correlated with vitamin A levels measured as retinol and retinyl palmitate. Mean concentrations of hepatic retinol ranged from 3mg /kg to 13 mg /kg, and from 0.35 mg /kg to 1.5mg /kg for renal retinol. Mean concentrations of hepatic retinyl palmitate ranged from 18 mg /kg to 146mg /kg, and 1mg /kg to 6mg/kg for renal retinyl palmitate. In 1999, molar ratio of renal retinol:retinyl palmitate was significantly and positively correlated with total polychlorinated dibenzodioxin (PCDD) concentration. Among sites, total PCDDs ranged from 5.4 ng /kg wet weight to 79.5 ng /kg wet weight in tree swallows. These results suggest that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries ...
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health of tree swallows Tachycineta bicolor nesting in pesticide sprayed apple orchards in ontario canada i immunological parameters
Journal of Toxicology and Environmental Health, 1998Co-Authors: Christine A Bishop, H J Boermans, Peggy Ng, G D Campbell, J StrugerAbstract:The degree of pesticide exposure and its effects on the immune system and its development were determined in 16-d-old tree swallow (Tachycineta bicolor) chicks from 4 sprayed apple orchards and three nonsprayed sites in southern Ontario, Canada, during 1994-1995. Persistent contaminant residues were measured in tree swallow eggs and in each chick hepatic ethoxyresorufin O -deethylase (EROD) activity; body, immune organ,and liver masses; lymphocyte blastogenesis response; respiratory burst and phagocytic responses; hematological evaluation; and histological development of thymus, bursa of fabricius, and spleen were determined. Chemicals sprayed on apple orchards were mainly ethylene bisdithiocarbamate and myclobutanil fungicides and organophosphorus, carbamate, and synthetic pyrethroid insecticides. During the period between oviposition of the first egg in each nest to d 16 after hatching, individual nests in orchards were exposed to between 4 and 11 individual chemical applications and up to 3 mixtures of...
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health of tree swallows Tachycineta bicolor nesting in pesticide sprayed apple orchards in ontario canada ii sex and thyroid hormone concentrations and testes development
Journal of Toxicology and Environmental Health, 1998Co-Authors: Christine A Bishop, Judit E G Smits, Peggy Ng, G Van Der Kraak, Alice HontelaAbstract:To investigate the effects of pesticides on wild birds, sex (17beta-estradiol; testosterone) and thyroid (triiodothyronine (T3) hormone concentrations, body mass, and testes mass were measured and the development of testes was evaluated in wild tree swallows (Tachycineta bicolor) nesting in four sprayed apple orchards and three nonsprayed sites in southern Ontario, Canada, in 1995-1996. In orchards, birds were exposed to as many as 11 individual spray events and five sprays of mixtures of chemicals. Residues of organochlorine pesticides, PCBs, lead, and arsenic concentrations were low and not variable among sites except p,p '-DDE concentrations, which ranged from 0.36 to 2.23 mug/ g wet weight in eggs. These persistent compounds were not correlated with any endocrine response measured in tree swallows. In 16-d-old male tree swallow chicks, body mass and concentrations of 17 -estradiol (estradiol), testosterone, and T3 in plasma showed no significant differences between sprayed and nonsprayed groups and am...
Judit E G Smits - One of the best experts on this subject based on the ideXlab platform.
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tree swallow Tachycineta bicolor nest success and nestling growth near oil sands mining operations in northeastern alberta canada
Canadian Journal of Zoology, 2019Co-Authors: Christine M Godwin, Robert M R Barclay, Judit E G SmitsAbstract:Industrial development and contaminant exposure may affect reproductive success and food quality for birds. Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) nesting near oil sands development i...
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variation in immune function body condition and feather corticosterone in nestling tree swallows Tachycineta bicolor on reclaimed wetlands in the athabasca oil sands alberta canada
Environmental Pollution, 2010Co-Authors: Jane N Harms, Gary R Bortolotti, Graham D Fairhurst, Judit E G SmitsAbstract:In the Athabasca oil sands region of northern Alberta, mining companies are evaluating reclamation using constructed wetlands for integration of tailings. From May to July 2008, reproductive performance of 40 breeding pairs of tree swallows (Tachycineta bicolor), plus growth and survival of nestlings, was measured on three reclaimed wetlands on two oil sands leases. A subset of nestlings was examined for i) feather corticosterone levels, ii) delayed-type hypersensitivity response, and iii) innate immune function. Nestlings on one of two wetlands created with oil sands process affected material (OSPM) were heavier and had greater wing-lengths, and mounted a stronger delayed-type hypersensitivity response compared those on the reference wetland. Corticosterone was significantly higher in male nestlings on one of two OSPM-containing wetland compared to the reference wetland. Body condition of 12-day-old female nestlings was inversely related to feather corticosterone. Under ideal weather conditions, reclaimed wetlands can support healthy populations of aerially-insectivorous birds.
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effects of exposure to naphthenic acids in tree swallows Tachycineta bicolor on the athabasca oil sands alberta canada
Journal of Toxicology and Environmental Health, 2007Co-Authors: Marieline Gentes, Cheryl Waldner, Zsuzsanna Papp, Judit E G SmitsAbstract:Naphthenic acids (NAs) are a group of carboxylic acids that are of particular concern to the steadily growing oil sands mining industry of Alberta, Canada, because they become highly concentrated in the water used for oil sands extraction and are toxic to aquatic biota and mammals. Upon mine closure, vast amounts of process-affected water will need to be reclaimed and proven safe for wildlife colonizing reclaimed areas. The effects of exposure to NAs have not been investigated in avian species. To address this void, tree swallow (Tachycineta bicolor) nestlings were dosed with NAs while being reared normally by their free-ranging parents on a site in the vicinity of the oil sands. Nestlings received 1.5 mg NAs/day (approximately 0.075 g/kg body mass) from d 7 to d 13 of age, which represented a 10-fold “worst exposure” scenario. Nestling growth, hematocrit, blood biochemistry, organ weights, and ethoxyresorufin O-deethylase (EROD) activity were unaffected by NAs. The only change detected on histopathologic...
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increased thyroid hormone levels in tree swallows Tachycineta bicolor on reclaimed wetlands of the athabasca oil sands
Archives of Environmental Contamination and Toxicology, 2007Co-Authors: Marieline Gentes, Cheryl Waldner, Anne Mcnabb, Judit E G SmitsAbstract:The oil sands of Alberta, Canada are one of the world’s largest reserves of crude oil. Oil sands mining companies are now investigating the ecological impacts of reclamation strategies in which wetlands are used for the bioremediation of waste materials. To examine the endocrine disrupting potential of chemicals in Oil Sands Process Materials (OSPM), thyroid hormone concentrations were measured in plasma and thyroid glands of nestling tree swallows (Tachycineta bicolor) from wetlands partly filled with mine tailings. Plasma triiodothyronine (T3) concentrations and thyroxine (T4) content within thyroid glands were elevated in nestlings from OSPM sites compared to those from the reference site. Results suggested enhanced hormone synthesis by the thyroid glands independently of activation of the pituitary–thyroid axis, as well as increased deiodination of T4 into T3 in peripheral tissues. This might have resulted from exposure to oil sands associated chemicals such as polycyclic aromatic hydrocarbons and from environmental factors such as food availability. Modulation of thyroid function might have negative effects on metabolism, behavior, feather development, and molt, which could compromise postfledging survival.
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effects of oil sands tailings compounds and harsh weather on mortality rates growth and detoxification efforts in nestling tree swallows Tachycineta bicolor
Environmental Pollution, 2006Co-Authors: Marieline Gentes, Cheryl Waldner, Zsuzsanna Papp, Judit E G SmitsAbstract:Oil sands mining companies in Alberta, Canada, are evaluating the feasibility of using wetlands to detoxify oil sands process material (OSPM) as a reclamation strategy. Reproductive success, nestling growth, survival and ethoxyresorufin-o-deethylase (EROD) activity were measured in tree swallows (Tachycineta bicolor) on experimental wetlands. In 2003, harsh weather triggered a widespread nestling die-off. Mortality rates on the control site reached 48% while they ranged from 59% to 100% on reclaimed wetlands. The odds of dying on the most process-affected sites were more than ten times higher than those on the control site. In 2004, weather was less challenging. Mortality rates were low, but nestlings on reclaimed wetlands weighed less than those on the control site, and had higher EROD activity. These results indicate that compared with reference birds, nestlings from OSPM-impacted wetlands may be less able to withstand additional stressors, which could decrease their chances of survival after fledging.
Ken Jock - One of the best experts on this subject based on the ideXlab platform.
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health of tree swallow Tachycineta bicolor nestlings exposed to chlorinated hydrocarbons in the st lawrence river basin part ii basal and stress plasma corticosterone concentrations
Journal of Toxicology and Environmental Health, 2003Co-Authors: Barbara Martinovic, Anne L Secord, Christine A Bishop, Erinn Birmingham, David R S Lean, Ken JockAbstract:: Sixteen-day-old tree swallows (Tachycineta bicolor) were collected in 1999 and 2000 from nine sites within the vicinity of the St. Lawrence River in Canada and the United States to determine if organochlorine contaminant concentrations correlated with corticosterone levels. Basal plasma corticosterone levels were determined in chicks reared in nest boxes, and stress plasma corticosterone levels were determined in chicks after exposure to a 10-min standardized stress test. Mean basal plasma corticosterone concentrations ranged from 4 to 37 ng/ml in 1999, and from 5 to 20 ng/ml in 2000. Mean poststress plasma corticosterone levels ranged from 26 to 67 ng/ml in 1999, and from 26 to 109 ng/ml in 2000. In 1999 and 2000, basal corticosterone was negatively correlated with polychlorinated dibenzofuran (PCDF). Total PCDFs ranged from 4.8 to 120.5 ng/kg wet weight in chicks in 1999 and 2000 among sites. These results indicate that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries may be interfering with the glucocorticoid endocrine axis of tree swallows.
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health of tree swallow Tachycineta bicolor nestlings exposed to chlorinated hydrocarbons in the st lawrence river basin part i renal and hepatic vitamin a concentrations
Journal of Toxicology and Environmental Health, 2003Co-Authors: Barbara Martinovic, Anne L Secord, Christine A Bishop, Erinn Birmingham, David R S Lean, Ken JockAbstract:Sixteen-day-old tree swallows (Tachycineta bicolor), near fledging, were collected in 1999 and 2000 from nine sites representing a gradient of dioxin concentrations, within the vicinity of the St. Lawrence River in Canada and the United States, to determine if organochlorine contaminants correlated with vitamin A levels measured as retinol and retinyl palmitate. Mean concentrations of hepatic retinol ranged from 3mg /kg to 13 mg /kg, and from 0.35 mg /kg to 1.5mg /kg for renal retinol. Mean concentrations of hepatic retinyl palmitate ranged from 18 mg /kg to 146mg /kg, and 1mg /kg to 6mg/kg for renal retinyl palmitate. In 1999, molar ratio of renal retinol:retinyl palmitate was significantly and positively correlated with total polychlorinated dibenzodioxin (PCDD) concentration. Among sites, total PCDDs ranged from 5.4 ng /kg wet weight to 79.5 ng /kg wet weight in tree swallows. These results suggest that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries ...
David W Winkler - One of the best experts on this subject based on the ideXlab platform.
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the environmental and genetic determinants of chick telomere length in tree swallows Tachycineta bicolor
Ecology and Evolution, 2019Co-Authors: Amos Belmaker, David W Winkler, Kelly K Hallinger, Rebbeca A Glynn, Mark F HaussmannAbstract:: Conditions during early life can have dramatic effects on adult characteristics and fitness. However, we still know little about the mechanisms that mediate these relationships. Telomere shortening is one possibility. Telomeres are long sequences of DNA that protect the ends of chromosomes. They shorten naturally throughout an individual's life, and individuals with short telomeres tend to have poorer health and reduced survival. Given this connection between telomere length (TL) and fitness, natural selection should favor individuals that are able to retain longer telomeres for a greater portion of their lives. However, the ability of natural selection to act on TL depends on the extent to which genetic and environmental factors influence TL. In this study, we experimentally enlarged broods of Tree Swallows (Tachycineta bicolor) to test the effects of demanding early-life conditions on TL, while simultaneously cross-fostering chicks to estimate heritable genetic influences on TL. In addition, we estimated the effects of parental age and chick sex on chick TL. We found that TL is highly heritable in Tree Swallow chicks, and that the maternal genetic basis for TL is stronger than is the paternal genetic basis. In contrast, the experimental manipulation of brood size had only a weak effect on chick TL, suggesting that the role of environmental factors in influencing TL early in life is limited. There was no effect of chick sex or parental age on chick TL. While these results are consistent with those reported in some studies, they are in conflict with others. These disparate conclusions might be attributable to the inherent complexity of telomere dynamics playing out differently in different populations or to study-specific variation in the age at which subjects were measured.
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solar powered radio tags reveal patterns of post fledging site visitation in adult and juvenile tree swallows Tachycineta bicolor
PLOS ONE, 2018Co-Authors: Teresa M Pegan, David P Craig, Eric R Gulsoncastillo, Richard Gabrielson, Wayne Bezner Kerr, Robert Maccurdy, Steven P Powell, David W WinklerAbstract:: The availability of small, lightweight tracking devices enhances our ability to study birds during mobile phases of their lives. Tree Swallows Tachycineta bicolor, a model species of wild songbird, are well-studied during their breeding season; but our understanding of their biology at other times of the year, when they are not tied to the fixed location of a nest, is more limited. We developed a lightweight radio tag with no battery (solar nanotag) to study the movements of small animals, and we deployed it to explore the behavior of Tree Swallows after the end of their summer breeding season. We tagged 32 breeding adult swallows and 36 juveniles and monitored their presence and absence at the breeding site during the post-fledging period. Although our observations are based on very small sample sizes, the tags revealed previously unknown patterns in Tree Swallow behavior during the post-breeding season. Some Tree Swallow fledglings continued to visit the site repeatedly in the months following the nesting season, with the latest detection occurring on September 30th; by contrast, all adults had permanently departed by the end of July. These results inform future hypotheses about post-breeding movements in Tree Swallows. But, more generally, the detection of tagged swallows on their distant wintering grounds, seven months after tagging, indicates the potential of studying small passerine movements throughout their entire lifetimes, and suggests a rich array of applications for these "Life Tags" to study the movements of small animals world-wide.
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Temperature effects on food supply and chick mortality in tree swallows (Tachycineta bicolor)
Oecologia, 2013Co-Authors: David W Winkler, Eldar RakhimberdievAbstract:Tree swallow ( Tachycineta bicolor ) breeding success in Ithaca, NY, USA, over the past quarter century has shown generally healthy fledgling production punctuated by years of high nestling mortality. This study tested the potential effects that temperature may have on the food supply and breeding success of swallows. Data from 17 years of daily insect samples were used to relate flying insect abundances to daily maximum temperatures and to define “cold snaps” as strings of consecutive days when the maximum temperatures did not exceed critical temperatures. The distributions of cold snaps and chick mortality events were investigated both through detailed reconstructions of the fates and fate dates of individual chicks, focused on the three breeding seasons of lowest fledging success, and with less detailed brood-level analyses of a larger 11-year dataset including years of more moderate mortality. Mark–recapture analyses of daily brood survival rate (DSR) reveal very strong support for the effects of cold temperatures on brood survival rates, and all the top models agree on a critical temperature of 18.5 °C for insect flight activity in Ithaca. The individual-level analyses, focused on years of higher mortality, favored a 3-day cold snap definition as the most predictive of DSR effects, whereas the larger-scale brood-level analyses revealed 1- and 2-day cold snaps as having the most significant effects on DSR. Regardless, all analyses reveal that, in an age of generally warmer climates, the largest effect of weather on swallow fledgling production is from cold temperatures.
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relative importance off environmental variables in determining the growth off nestling tree swallows Tachycineta bicolor
Ibis, 2008Co-Authors: John P Mccarty, David W WinklerAbstract:Unpredictable, short-term changes in environmental conditions associated with weather patterns have severe impacts on the reproductive success of Tree Swallows Tachycineta bicolor, as well as other aerial insectivores. We examined the effects of day-to-day environmental variation on the growth of nestling Tree Swallows. Using path analysis, we compared the relative importance of changes in food availability, ambient temperature and wind speed on changes in mass and feather length over four years at our study site near Ithaca, New York. Changes in environmental conditions explained a significant amount of the variation in nestling growth, with daily high temperature having the greatest influence for nestlings younger than five days. Both food supply and temperature had significant direct effects on growth of nestlings older than nine days, with temperature also having a significant indirect effect through its influence on food availability. For both young and old chicks, mass gains were smaller for chicks hatched later in the season. Environmental conditions also explained a significant amount of the linear growth of the ninth primary feather in one of two years, with food supply showing the most consistent positive effect. Environmental conditions several days prior to the measurements significantly influenced feather growth, indicating that the effects of adverse conditions are spread out over several days of feather growth, but this effect was not seen for change in mass.
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individual quality and food availability determine yolk and egg mass and egg composition in tree swallows Tachycineta bicolor
Journal of Avian Biology, 2006Co-Authors: Daniel R Ardia, Matthew F Wasson, David W WinklerAbstract:Variation in egg size and composition can have important consequences for the quality of offspring. We investigated the factors influencing the yolk mass and egg mass of tree swallows breeding in Ithaca, NY. Using a nondestructive technique to estimate yolk mass via standardized digital-candler photographs, we compared yolk size and egg size of tree swallows Tachycineta bicolor in response to variation in food availability and individual quality. Insect availability one to three days prior to laying, but not four to six days, predicted yolk mass, while insect availability two to three days prior to laying predicted total egg mass. This suggests that, while eggs are formed over longer periods, food availability closer to time of laying has the greatest influence on egg size. These results were supported by collected eggs, as yolk rings revealed that tree swallow eggs are formed over 5–6 days. There was an influence of female quality as well, with early laying birds, independent of food availability, laying larger eggs. Eggs laid later in the laying sequence had larger yolks and greater egg mass. Overall, variation in egg quality appears to be due to a combination of environmental conditions, reflected in food resources, individual quality, and allocation tradeoffs during the laying period.
Thomas W Custer - One of the best experts on this subject based on the ideXlab platform.
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element concentrations in tree swallows Tachycineta bicolor from the u s and binational great lakes areas of concern
Archives of Environmental Contamination and Toxicology, 2019Co-Authors: Thomas W Custer, Christine M Custer, Diana R Goldberg, Paul M Dummer, Christian J FransonAbstract:Selected elements were targeted in state Remedial Action Plans as one group of chemicals affecting the Beneficial Use Impairments of Great Lakes Areas of Concern (AOCs). Livers of nestling tree swallows, Tachycineta bicolor, were harvested from 76 sites in the Great Lakes, which included multiple sites at 27 AOCs and 12 reference sites from 2010 to 2015, and were analyzed for 21 elements. Mercury concentrations were at background levels at all sites. Elevated cadmium (Cd) concentrations were associated with industry. The highest Cd values were from the Black River, OH AOC and were associated with historic coke production but were not at toxic levels. Lead (Pb) concentrations were highest on the Rouge River, MI AOC—the oldest and most heavily populated and industrialized area in southeast Michigan. Individual Pb concentrations were elevated to a level associated with delta-aminolaevulinic acid dehydratase inhibition but not to a level considered toxic. In contrast, livers harvested from sites on the southwest shore of Lake Michigan had selenium (Se) concentrations elevated to levels associated with reduced avian reproduction. One likely source of the high Se concentrations was pollution from a local coal-fired power plant. Concentrations of the remaining elements were at background levels.
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annual variation in polychlorinated biphenyl pcb exposure in tree swallow Tachycineta bicolor eggs and nestlings at great lakes restoration initiative glri study sites
Environmental Monitoring and Assessment, 2018Co-Authors: Christine M Custer, Thomas W Custer, P M H Dummer, Diana R Goldberg, Christian J FransonAbstract:Tree swallow (Tachycineta bicolor) eggs and nestlings were collected from 16 sites across the Great Lakes to quantify normal annual variation in total polychlorinated biphenyl (PCB) exposure and to validate the sample size choice in earlier work. A sample size of five eggs or five nestlings per site was adequate to quantify exposure to PCBs in tree swallows given the current exposure levels and variation. There was no difference in PCB exposure in two randomly selected sets of five eggs collected in the same year, but analyzed in different years. Additionally, there was only modest annual variation in exposure, with between 69% (nestlings) and 73% (eggs) of sites having no differences between years. There was a tendency, both statistically and qualitatively, for there to be less exposure in the second year compared to the first year.
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organic contamination in tree swallow Tachycineta bicolor nestlings at united states and binational great lakes areas of concern
Environmental Toxicology and Chemistry, 2017Co-Authors: Thomas W Custer, Christine M Custer, Christian J Franson, Diana R Goldberg, Paul M Dummer, Richard A. EricksonAbstract:Contaminant exposure of tree swallows, Tachycineta bicolor, nesting in 27 Areas of Concern (AOC) in the Great Lakes' basin was assessed from 2010 to 2014 to assist managers and regulators in their assessments of Great Lakes AOCs. Contaminant concentrations in nestlings from AOCs were compared to nestlings from nearby non-AOC sites. Polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) concentrations in tree swallow nestling carcasses at 30% and 33% of AOCs were below the mean concentration for non-AOCs. Polycyclic aromatic hydrocarbon (PAH) concentrations in nestling stomach contents and perfluorinated compound (PFC) concentrations in nestling plasma at 67% and 64% of AOCs were below the mean concentration for non-AOCs. Concentrations of PCBs in nestling carcasses were elevated at some AOCs, but were modest compared to highly PCB-contaminated sites where reproductive effects have been documented. Concentrations of PAHs in diet were sufficiently elevated at some AOCs to elicit a measurable physiological response. Among AOCs, the PFC compound perfluorooctane sulfonate concentrations in plasma were the highest on the River Raisin, MI (geometric mean 330 ng/ml), but well below an estimated toxicity reference value (1,700 ng/ml). Both PAH and PCB concentrations in nestling stomach contents, and PCBs in carcasses, were significantly correlated with concentrations in sediment reported in another study, thereby reinforcing the utility of using tree swallows to assess bioavailability of sediment contamination. This article is protected by copyright. All rights reserved
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Chromosomal damage and EROD induction in tree swallows (Tachycineta bicolor) along the Upper Mississippi River, Minnesota, USA
Ecotoxicology, 2015Co-Authors: Emilie Bigorgne, Thomas W Custer, Christine M Custer, Paul M Dummer, Richard A. Erickson, Natalie Karouna-renier, Sandra Schultz, Wayne E. Thogmartin, Cole W. MatsonAbstract:The health of tree swallows, Tachycineta bicolor, on the Upper Mississippi River (UMR) was assessed in 2010 and 2011 using biomarkers at six sites downriver of Minneapolis/St. Paul, MN metropolitan area, a tributary into the UMR, and a nearby lake. Chromosomal damage was evaluated in nestling blood by measuring the coefficient of variation of DNA content (DNA CV) using flow cytometry. Cytochrome P450 1A activity in nestling liver was measured using the ethoxyresorufin- O -dealkylase (EROD) assay, and oxidative stress was estimated in nestling livers via determination of thiobarbituric acid reacting substances (TBARS), reduced glutathione (GSH), oxidized glutathione (GSSG), the ratio GSSG/GSH, total sulfhydryl, and protein bound sulfhydryl (PBSH). A multilevel regression model (DNA CV) and simple regressions (EROD and oxidative stress) were used to evaluate biomarker responses for each location. Chromosomal damage was significantly elevated at two sites on the UMR (Pigs Eye and Pool 2) relative to the Green Mountain Lake reference site, while the induction of EROD activity was only observed at Pigs Eye. No measures of oxidative stress differed among sites. Multivariate analysis confirmed an increased DNA CV at Pigs Eye and Pool 2, and elevated EROD activity at Pigs Eye. These results suggest that the health of tree swallows has been altered at the DNA level at Pigs Eye and Pool 2 sites, and at the physiological level at Pigs Eye site only.
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changes in polychlorinated biphenyl pcb exposure in tree swallows Tachycineta bicolor nesting along the sheboygan river wi usa
Ecotoxicology, 2014Co-Authors: Christine M Custer, Thomas W Custer, Sean M Strom, Kathleen A Patnode, Christian J FransonAbstract:Exposure to polychlorinated biphenyls (PCBs) in tree swallow (Tachycineta bicolor) eggs on the Sheboygan River, Wisconsin in the 1990s was higher at sites downstream (geometric means = 3.33–8.69 μg/g wet wt.) of the putative PCB source in Sheboygan Falls, Wisconsin than it was above the source (1.24 μg/g) with the exposure declining as the distance downstream of the source increased. A similar pattern of declining exposure was present in the 2010s as well. Although exposure to PCBs in eggs along the Sheboygan River at sites downstream of Sheboygan Falls has declined by ~60 % since the mid-1990s (8.69 down to 3.27 μg/g) there still seems to be residual pockets of contamination that are exposing some individuals (~25 %) to PCB contamination, similar to exposure found in the 1990s. The exposure patterns in eggs and nestlings among sites, and the changes between the two decades, are further validated by accumulation rate information.
