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Dr. Eagles-Smith is a Research Ecologist with the Corvallis Reseach Group in Corvallis, Oregon. His research focuses on the interactions among ecological processes, contaminant bioaccumulation, and effects on wild populations. His work specifically focuses on (1) the ecological factors regulating contaminant bioaccumulation and trophic transfer, with an emphasis on food web processes and contaminant cycling, (2) land use practices and ecosystem restoration effects on contaminant cycling through food webs, and (3) the sublethal effects of contaminants on individuals and contaminant-induced impairment to reproduction in the wild. Dr. Eagles-Smith's research is broadly applied across taxa (primarily fish and waterbirds) and habitat types (including lakes, freshwater wetlands, agricultural fields, and estuarine habitats).
Ph.D. Ecology. University of California, Davis (2006)
B.S. (Magna Cum Laude) Env. Resource Sciences.
University of California, Davis (2000)
Supervisory Research Ecologist, USGS, FRESC, Corvallis Research Group (8/07-3/2010).
Wildlife Biologist, USGS, WERC, UC Davis Field Station (8/07-3/2010).
Senior Biologist, US Fish and Wildlife Service, Sacramento (2/07-8/07).
Staff Biologist, US Fish and Wildlife Service, Sacramento (2/03-2/07).
Doctoral Research, Dept. of Wildlife, Fish and Cons. Biology, UC Davis (9/00-11/06).
Staff Research Assistant, Dept. of Wildlife, Fish and Cons. Biology, UC Davis (2/98-9/00).
Stable isotope applications to ecosystem energetics, food web ecology, fish and avian foraging ecology, mercury bioaccumulation in aquatic food webs, mercury effects on waterbirds, mercury bioaccumulation in waterbirds, avian reproductive ecology.
Science and Products
In a study designed to help resource managers when considering mercury exposure risk, scientists determined that sulfur cycling—a process closely related to mercury methylation rates—and ecological conditions that influence exposure are important factors affecting fish mercury concentrations in estuarine wetlands.
The FRESC Contaminant Ecology research program evaluates the distribution, movement, and ecological effects of environmental contaminants across the landscape and strives to provide relevant science in support of natural resource conservation, management, and decision making.
Mercury contamination is a serious issue that impacts both ecosystem and human health on a global scale. In its organic (methylmercury) form, mercury is highly bioaccumulative and is among the most toxic compounds commonly found in the environment. Mercury is a relatively distinctive contaminant in the sense that the risk of deleterious environmental effects is more strongly related to...
The distribution and occurrence of contaminants and the associated biological exposure in ecological systems are driven by complex interactions between contaminant sources and mobilization pathways that are overlaid upon the habitat requirements of at-risk organisms. Moreover, landscape structure and land uses can strongly influence the driving processes of contaminant cycling, as well as the...
Whereas the other themes of the Contaminant Ecology Research Program focus on where, why, and how contaminants cycle and bioaccumulate in ecological systems, this theme is focused on determining what happens at environmentally relevant concentrations.
This is a broad theme representing the largest component of the Contaminant Ecology Research Program, acting as a bridge between the “Habitat and Land Use Influences” and “Ecological Effects” themes. “Contaminant Bioaccumulation” focuses on quantifying the transfer or movement of contaminants through food webs, and identifying the primary landscape factors and ecological mechanisms that are...
Mercury cycling, bioaccumulation, and risk across western North America: a landscape scale synthesis linking long-term datasets
Mercury (Hg) is a serious environmental problem that is impacting ecological and human health on a global scale. However, local and regional processes are largely responsible for producing methylmercury, which drives ecological risk. This is particularly true in western North America where the combination of diverse landscapes, habitat types, climates, and Hg sources may disproportionally...
Summary of total mercury concentrations in dragonfly larvae, western mosquitofish, and tree swallow eggs collected from Cosumnes River Preserve 2011 – 2013
In order to document potential environmental health risk in Cosumnes River Preserve wetlands due to mercury, we analyzed dragonfly larvae, western mosquitofish, and tree swallow eggs collected from wetlands and rice fields of the Preserve from 2011 to 2013.
The dataset includes the bird species, sex, mercury concentration in breast feathers and whole blood, and the composite measure of fluctuating asymmetry. Statistical models were developed for each species to analyze the relationship between mercury exposure in either breast feathers or whole blood and the composite measure of fluctuating asymmetry, while accounting for the sex of each bird....
The dataset includes specifics on fragments of bullets recovered from shot Belding's ground squirrels from Oregon and California. Ground squirrels were radiographed and then we used ImageJ software to count and measure the area of those bullet fragments.
Total Mercury Concentrations in Fish Muscle from the Colorado River and Bright Angel Creek, AZ, USA (2015)
This dataset contains data on the length, mass, and muscle total mercury concentration of Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) collected from the Colorado River in Glen Canyon National Recreation Area (GLCA) and Grand Canyon National Park (GRCA), and Bright Angel Creek in GRCA.
Mercury and lead exposure in avian scavengers from the Pacific Northwest suggest risks to California condors: Implications for reintroduction and recovery
Mercury (Hg) and lead (Pb) are widespread contaminants that pose risks to avian scavengers. In fact, Pb exposure is the primary factor limiting population recovery in the endangered California condor (Gymnogyps californianus) and Hg can impair avian reproduction at environmentally relevant exposures. The Pacific Northwest region of the...Herring, Garth; Eagles-Smith, Collin A.; Varland, Daniel E.
Mercury on a landscape scale—Balancing regional export with wildlife health
The Cosumnes River watershed requires a 57–64 percent reduction in loads to meet the new Delta methylmercury (MeHg) total maximum daily load allocation, established by the Central Valley Regional Water Quality Control Board. Because there are no large point sources of MeHg in the watershed, the focus of MeHg load reductions will fall upon non-...Marvin-DiPasquale, Mark C.; Windham-Myers, Lisamarie; Fleck, Jacob A.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; McQuillen, Harry
Critically assessing the utility of portable lead analyzers for wildlife conservation
Lead (Pb) exposure in wildlife is a widespread management and conservation concern. Quantitative determination of Pb concentrations in wildlife tissues is the foundation for estimating exposure and risk. Development of low‐cost, portable instruments has improved access and cost‐effectiveness of determining Pb concentrations in blood samples, while...Herring, Garth; Eagles-Smith, Collin A.; Bedrosian, Bryan; Craighead, Derek; Domenech, Robert; Langner, Heiko W.; Parish, Chris N.; Shreading, Adam; Welch, Alacia; Wolstenholme, Rachel
Prey fish returned to Forster’s tern colonies suggest spatial and temporal differences in fish composition and availability
Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster’s tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay...Peterson, Sarah H.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark P.; Hartman, C. Alex
Mercury concentrations in multiple tissues of Kittlitz's murrelets (Brachyramphus brevirostris)
Mercury (Hg) is a non-essential, toxic metal that is distributed worldwide. Mercury biomagnifies in food webs and can threaten the health of top predators such as seabirds. The Kittlitz's murrelet (Brachyramphus brevirostris) is a seabird endemic to Alaska and the Russian Far East and is a species of conservation concern in the region. We...Kenney, Leah A.; Kaler, Robb S.; Kissling, Michelle L.; Bond, Alexander L.; Eagles-Smith, Collin A.
Modulators of mercury risk to wildlife and humans in the context of rapid global change
Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like...Eagles-Smith, Collin A.; Silbergeld, Ellen K.; Basu, Niladri; Bustamante, Paco; Diaz-Barriga, Fernando; Hopkins, William A.; Kidd, Karen A.; Nyland, Jennifer F.
Characterizing Golden Eagle risk to lead and anticoagulant rodenticide exposure: A review
Contaminant exposure is among the many threats to Golden Eagle (Aquila chrysaetos) populations throughout North America, particularly lead poisoning and anticoagulant rodenticides (AR). These threats may act in concert with others (e.g., lead poisoning and trauma associated with striking objects) to exacerbate risk. Golden Eagles are skilled...Herring, Garth; Eagles-Smith, Collin A.; Buck, Jeremy A.
Correlates of immune defenses in golden eagle nestlings
An individual's investment in constitutive immune defenses depends on both intrinsic and extrinsic factors. We examined how Leucocytozoon parasite presence, body condition (scaled mass), heterophil-to-lymphocyte (H:L) ratio, sex, and age affected immune defenses in golden eagle (Aquila chrysaetos) nestlings from three regions:...MacColl, Elisabeth; Vanesky, Kris; Buck, Jeremy A.; Dudek, Benjamin; Eagles-Smith, Collin A.; Heath, Julie A.; Herring, Garth; Vennum, Chris; Downs, Cynthia J.
Selenium: Mercury molar ratios in freshwater fish in the Columbia River Basin: Potential applications for specific fish consumption advisories
Fish provide a valuable source of beneficial nutrients and are an excellent source of low fat protein. However, fish are also the primary source of methylmercury exposure in humans. Selenium often co-occurs with mercury and there is some evidence that selenium can protect against mercury toxicity yet States issue fish consumption advisories based...Cusack, Leanne K.; Eagles-Smith, Collin A.; Harding, Anna K.; Kile, Molly; Stone, Dave
Season, molt, and body size influence mercury concentrations in grebes
We studied seasonal and physiological influences on mercury concentrations in western grebes (Aechmophorus occidentalis) and Clark's grebes (A. occidentalis) across 29 lakes and reservoirs in California, USA. Additionally, at three of these lakes, we conducted a time series study, in which we repeatedly sampled grebe blood mercury concentrations...Hartman, Christopher; Ackerman, Joshua T.; Herzog, Mark P.; Eagles-Smith, Collin A.
Bioenergetics models to estimate numbers of larval lampreys consumed by smallmouth bass in Elk Creek, Oregon
Nonnative fishes have been increasingly implicated in the decline of native fishes in the Pacific Northwest. Smallmouth Bass Micropterus dolomieu were introduced into the Umpqua River in southwest Oregon in the early 1960s. The spread of Smallmouth Bass throughout the basin coincided with a decline in counts of upstream-migrating Pacific Lampreys...Schultz, Luke; Heck, Michael; Kowalski, Brandon M; Eagles-Smith, Collin A.; Coates, Kelly C.; Dunham, Jason B.
A critical evaluation of the utility of eggshells for estimating mercury concentrations in avian eggs
Eggshells are a potential tool for non-lethally sampling contaminant concentrations in bird eggs, yet few studies have examined their utility to represent mercury exposure. We assessed mercury concentrations in eggshell components for 23 bird species and determined whether they correlated with total mercury (THg) in egg contents. We designed a...Peterson, Sarah H.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Hartman, C. Alex; Herzog, Mark P.
Potential reintroduction of the endangered California Condor to parts of its historic range in the Pacific Northwest would benefit from information on possible threats that could challenge recovery efforts. Exposure to environmental contaminants is a key limiting factor for condor recovery in its southern range.
Mercury is a widespread pollutant that poses health risks to humans and wildlife at a global scale. Addressing these risks requires science-based integrated policy approaches.
The Cosumnes River watershed has seasonal, non-point source hotspots for total mercury and methylmercury production, which discharge to the Sacramento-San Joaquin River Delta in north-central California. To reduce mercury loads to the Delta, researchers created open-water deep cells at the downstream end of wetlands.
Lead exposure in wildlife is a widespread management and conservation concern. Low-cost, portable lead analyzers have improved access and cost-effectiveness of determining lead concentrations in animal blood samples, yet analytical bias and lack of quality-assurance–quality-control measures can confound results.
USGS author Collin Eagles-Smith led an invited synthesis paper as part of the plenary effort for the 13th International Conference on Mercury as a Global Contaminant.
Timber harvest is a significant driver of mercury releases in some parts of the world. Yet, the impact of forest harvest on mercury mobilization has not been directly studied in the Pacific Northwest despite being an important timber producing region that also receives high atmospheric mercury deposition.
Mercury contamination is widespread, at various levels across western North America in air, soil, sediment, plants, fish and wildlife.