Tree swallow, Tachycineta bicolor, nestlings were collected from 60 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 6 sites not listed as AOCs from 2010 to 2014. Nestlings were measured for ethoxyresorufin-O-dealkylase (EROD) activity, chromosomal damage (DNA CV), and six measures of oxidative stress. Each of these bioindicators was divided into four groups from the highest to lowest values and the groups were compared to contaminant concentrations using multivariate analysis. Nestling contaminant concentrations included polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), and 17 elements. Alkylated polycyclic aromatic hydrocarbons (aPAHs), parent PAHs (pPAHs) were measured in pooled nestling dietary samples. Sibling egg data including measurements of dioxins and selected pesticides were also included in the analysis. Concentrations of aPAHs, pPAHs, and PCBs, in that order, were the major contributors to the significant differences between the lowest and highest EROD activity groups; the pesticides chlordane, heptachlor, and dieldrin were of secondary importance. PBDEs and PFCs were of lower importance and the remaining pesticides and elements contributed very little. PAH toxic equivalents, dieldrin, heptachlor, and chlordane, in that order, were the major contributors to the difference between the low and the two highest groups of DNA CV; pPAHs and aPAHs were or secondary importance. The four categories of reduced glutathione (GSH) and the ratio oxidized glutathione (GSSG)/GSH were not significantly different. There were significant differences among categories of thiobarbituric acid reacting substances (TBARS), GSSG, total sulfhydryl (TSH), and protein bound sulfhydryl (PBSH); however, the individual categories of low to high values barely differed from one another.

Tree swallow, Tachycineta bicolor, nestlings were collected from 60 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 6 sites not listed as AOCs from 2010 to 2014. Nestlings were measured for ethoxyresorufin-O-dealkylase (EROD) activity, chromosomal damage (DNA CV), and six measures of oxidative stress. Each of these bioindicators was divided into four groups from the highest to lowest values and the groups were compared to contaminant concentrations using multivariate analysis. Nestling contaminant concentrations included polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), and 17 elements. Alkylated polycyclic aromatic hydrocarbons (aPAHs), parent PAHs (pPAHs) were measured in pooled nestling dietary samples. Sibling egg data including measurements of dioxins and selected pesticides were also included in the analysis. Concentrations of aPAHs, pPAHs, and PCBs, in that order, were the major contributors to the significant differences between the lowest and highest EROD activity groups; the pesticides chlordane, heptachlor, and dieldrin were of secondary importance. PBDEs and PFCs were of lower importance and the remaining pesticides and elements contributed very little. PAH toxic equivalents, dieldrin, heptachlor, and chlordane, in that order, were the major contributors to the difference between the low and the two highest groups of DNA CV; pPAHs and aPAHs were or secondary importance. The four categories of reduced glutathione (GSH) and the ratio oxidized glutathione (GSSG)/GSH were not significantly different. There were significant differences among categories of thiobarbituric acid reacting substances (TBARS), GSSG, total sulfhydryl (TSH), and protein bound sulfhydryl (PBSH); however, the individual categories of low to high values barely differed from one another.

Analysis of biological tissues or direct sources of food may better characterize exposure of non-target organisms to current-use pesticides. Food boluses were collected from tree swallow (Tachycineta bicolor) nestlings using a non-lethal, ligature method and were composited based on nest. The ligatures, which prevented the bolus from being swallowed, were placed on nestlings for 1 h until samples were collected. Samples in 2016 were collected from nestlings at 6 days and 12 days post-hatch whereas 2018 samples were collected from nestlings at 12 days post-hatch. Furthermore, in 2016 and 2018, insects commonly consumed by tree swallows were collected via sweep net and composited based on suborder (Brachycera, Nematocera, Zygoptera, or other) following identification via dichotomous keys. All samples were collected from an agricultural region of central Saskatchewan, Canada. Samples were freeze-dried and homogenized prior to extraction. A subsample was removed for analysis (the whole sample was used for those with a total mass less than 0.1 g). Following pressurized liquid extraction with 50/50 (v/v) acetone/dichloromethane, samples were cleaned-up via pass-through solid phase extraction using Oasis PRiME HLB cartridges (3 cc, 150 mg). All samples were analyzed for 170 current-use pesticides using gas chromatography and liquid chromatography tandem mass spectrometry (GC/MS/MS and LC/MS/MS). A total of 24 current-use pesticides and metabolites were detected in bolus samples (0.3-784.3 ng/g) and 19 current-use pesticides were detected in insects (0.2-1169.6 ng/g).

During 2010-2014, tree swallow (Tachycineta bicolor) reproductive success was monitored at 68 sites across all 5 Great Lakes, including 58 sites located within Great Lakes Areas of concern (AOCs) and 10 non-AOCs. Sample eggs were collected from tree swallow clutches and analyzed for contaminants including polychlorinated biphenyls (PCBs), dioxin and furans, polybrominated diphenyl ethers, and 34 other organic compounds. Contaminant data were available for 360 of the 1249 clutches monitored. Markov chain multistate modeling was used to assess the importance of 5 ecological and 11 of the dominant contaminants in explaining the pattern of egg and nestling failure rates. Four of 5 ecological variables (female Age, Date within season, Year, and Site) were important explanatory variables. Of the 11 contaminants, only total dioxin and furan toxic equivalents (TEQs) explained a significant amount of the egg failure probabilities. Neither total PCBs nor PCB TEQs explained the variation in egg failure rates. In a separate analysis, polycyclic aromatic hydrocarbon exposure in nestling diet was significantly correlated with the daily probability of egg failure. The eight sites within AOCs which had poorer reproduction when compared to 9 non-AOC sites, the measure of impaired reproduction as define by the Great Lakes Restoration Initiative, were associated with exposure to dioxins and furans, PAHs, or depredation. Only 2 sites had poorer reproduction than the poorest performing non-AOC. Using a classic (non-modeling) approach to estimating reproductive success, 82% of nests hatched at least 1 egg, and 75% of eggs hatched.

A site in north eastern MI, Oscoda Township, has some of the highest recorded exposure in birds to perfluorinated substances (PFASs) in the U.S. Some egg and plasma concentrations at that location exceeded the lowest reproductive effect threshold established for two avian laboratory species. The objectives of this study were to determine whether there were reproductive effects or physiological responses in a model bird species, the tree swallow (Tachycineta bicolor), associated with this extremely high exposure to PFASs. The lack of exposure above background to other contaminants at this site allowed for an assessment of PFAS effects without the complication that responses may be caused by other contaminants. A secondary objective was to determine the distribution of PFASs in multiple tissue types to better understand and interpret residues in different tissues. This can best be done at highly exposed locations where tissue concentrations would be expected to be above detectable levels if they are present in that tissue. There were no demonstrable effects of PFAS exposure on reproduction nor on most physiological responses.

Exposure to multiple classes of contaminants, both legacy and those of emerging concern (CECs), were assessed in tree swallow (Tachycineta bicolor) tissue and diet samples from 6 sites along the Maumee River, OH to understand both exposure and possible effects of exposure to those CECs for which there is little avian data. The six sites represented a gradient from intensive agriculture upstream to highly urbanized and industrial landscapes downstream; 1 – 2 remote Wisconsin lakes were assessed for comparative purposes. Cytochrome P450 induction, DNA damage, and thyroid function were also assessed relative to contaminant exposure. Bioaccumulative CECs, such as polybrominated diphenyl ethers (PBDEs) and perfluorinated substances, did not follow any upstream to downstream gradient, but both had significantly greater concentrations along the Maumee River than at the remote lake sites. Greater exposure to PBDEs was apparent in swallows at or near wastewater treatment facilities than at other sites. Total polychlorinated biphenyl and total polycyclic aromatic hydrocarbon concentrations were at greater concentrations in swallows at downstream locations compared to upstream sites and were associated with higher ethoxyresorufin-O-dealkylase activity. Few herbicides or non-organochlorine insecticides were detected in swallow tissues or their food, except for atrazine and its metabolite desethylatrazine, the latter of which was detected in all food samples, eggs, and nearly all nestling carcasses from along the Maumee River. Few pharmaceuticals and personal care products were detected in tree swallow tissue or sediment samples except for DEET and iopamidol. Both were detected in most liver samples, but not in eggs, and were detected at the remote lake sites as well. This is one of the most comprehensive assessments to date of exposure and effects of CECs in birds.

Vector datasets of CWHR range maps are one component of California Wildlife Habitat Relationships (CWHR), a comprehensive information system and predictive model for Californias wildlife. The CWHR System was developed to support habitat conservation and management, land use planning, impact assessment, education, and research involving terrestrial vertebrates in California. CWHR contains information on life history, management status, geographic distribution, and habitat relationships for wildlife species known to occur regularly in California. Range maps represent the maximum, current geographic extent of each species within California. They were originally delineated at a scale of 1:5,000,000 by species-level experts and have gradually been revised at a scale of 1:1,000,000. For more information about CWHR, visit the CWHR webpage (https://www.wildlife.ca.gov/Data/CWHR). The webpage provides links to download CWHR data and user documents such as a look up table of available range maps including species code, species name, and range map revision history; a full set of CWHR GIS data; .pdf files of each range map or species life history accounts; and a User Guide.

Tree swallow, Tachycineta bicolor, nestlings were collected from 76 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 12 sites not listed as AOCs from 2010 to 2015. Livers were harvested and analyzed for 21 elements. Mercury concentrations differed among AOCs; however, all livers analyzed had concentrations well within background and generally comparable or lower than most sites outside of the Great Lakes. Mercury, the only element specifically identified in the designation of AOCs, does not seem to pose a threat to birds at any of the AOCs monitored. In contrast, selenium (Se) concentrations were elevated at sites on the southwest shore of Lake Michigan to levels that could be harmful to reproduction. Other toxic elements were elevated at selected AOCs, but the concentrations were not at toxic levels. Multivariate analysis identified concentration pattern differences among 8 AOCs that had 3 or more sites sampled. Of 29 possible AOC comparisons, 11 were significant and clear differences in patterns were evident. Concentration patterns of sites within AOCs appeared closely associated with one another. Additionally, Se was the primary contributor to the differences among the 8 AOCs for 9 of the 11 comparisons.

Tree swallow, Tachycineta bicolor, nestlings were collected from 76 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 12 sites not listed as AOCs from 2010 to 2015. Livers were harvested and analyzed for 21 elements. Mercury concentrations differed among AOCs; however, all livers analyzed had concentrations well within background and generally comparable or lower than most sites outside of the Great Lakes. Mercury, the only element specifically identified in the designation of AOCs, does not seem to pose a threat to birds at any of the AOCs monitored. In contrast, selenium (Se) concentrations were elevated at sites on the southwest shore of Lake Michigan to levels that could be harmful to reproduction. Other toxic elements were elevated at selected AOCs, but the concentrations were not at toxic levels. Multivariate analysis identified concentration pattern differences among 8 AOCs that had 3 or more sites sampled. Of 29 possible AOC comparisons, 11 were significant and clear differences in patterns were evident. Concentration patterns of sites within AOCs appeared closely associated with one another. Additionally, Se was the primary contributor to the differences among the 8 AOCs for 9 of the 11 comparisons.

These metadata provide data used to examine tree swallow incubation behavior in relation to egg mercury concentration and maternal blood mercury concentration. These data were collected from tree swallows nesting in artificial wooden nest boxes at the Cosumnes River Preserved in California's Central Valley in 2014. Included are two datasets. One dataset provides daily incubation constancy (the proportion of the day the female spent incubating her eggs), the number of incubation recesses (breaks from incubating) taken by the attending female each day and the total mercury concentration of one egg from the female's clutch, and blood total mercury concentrations collected from the mother. Additionally, we include other ecological covariates: NestID, date, julian date, nest age, full clutch size, and ambient temperature within the nestbox. The second dataset provides the length in minutes of each individual incubation recess as well as the total mercury concentration of one egg from the female's clutch, blood total mercury concentrations collected from the mother, and ecological covariates NestID, date, julian date, nest age, full clutch size, and ambient temperature within the nestbox. These data support the following publication: Hartman, C.A., Ackerman, J.T. and Herzog, M.P., 2019. Mercury exposure and altered parental nesting behavior in a wild songbird. Environmental Science & Technology. 53(9), 5396-5405. https://doi.org/10.1021/acs.est.8b07227