The Oil Pollution Act of 1990 establishes liability for injuries to natural resources because of the release or threat of release of oil. Assessment of injury to natural resources resulting from an oil spill and development and implementation of a plan for the restoration, rehabilitation, replacement or acquisition of natural resources to compensate for those injuries is accomplished through the Natural Resource Damage Assessment (NRDA) process. The NRDA process began within a week of the Deepwater Horizon oil spill, which occurred on April 20, 2010. During the spill, more than 8500 dead and impaired birds representing at least 93 avian species were collected. In addition, there were more than 3500 birds observed to be visibly oiled. While information in the literature at the time helped to identify some of the effects of oil on birds, it was not sufficient to fully characterize the nature and extent of the injuries to the thousands of live oiled birds, or to quantify those injuries in terms of effects on bird viability. As a result, the US Fish and Wildlife Service proposed various assessment activities to inform NRDA injury determination and quantification analyses associated with the Deepwater Horizon oil spill, including avian toxicity studies. The goal of these studies was to evaluate the effects of oral exposure to 1-20ml of artificially weathered Mississippi Canyon 252 oil kg bw day from one to 28 days or one to five applications of oil to 20% of the bird's surface area. It was thought that these exposure levels would not result in immediate or short-term mortality but might result in physiological effects that ultimately could affect avian survival, reproduction and health. These studies included oral dosing studies, an external dosing study, metabolic and flight performance studies and field-based flight studies. Results of these studies indicated changes in hematologic endpoints including formation of Heinz bodies and changes in cell counts. There were also effects on multiple organ systems, cardiac function and oxidative status. External oiling affected flight patterns and time spent during flight tasks indicating that migration may be affected by short-term repeated exposure to oil. Feather damage also resulted in increased heat loss and energetic demands. The papers in this special issue indicate that the combined effects of oil toxicity and feather effects in avian species, even in the case of relatively light oiling, can significantly affect the overall health of birds.

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Ecological risk assessment as currently practiced has hindered consideration of ecosystem services endpoints and restoration goals in the environmental management process. Practitioners have created barriers between procedures to clean up contaminated areas and efforts to restore ecosystem functions. In this article, we examine linkages between contaminant risk assessment approaches and restoration efforts with the aim of identifying ways to improve environmental outcomes. We advocate that project managers and other stakeholders use an ecological planning framework, with restoration options included upfront in the risk assessment. We also considered the opportunities to incorporate ecosystem services as potential assessment endpoints in the Problem Formulation stages of a risk assessment. Indeed, diverse perspectives of stakeholders are central to understand the relevance of social, cultural, economic, and regional ecology as influences on future use options for the landscape being restored. The measurement endpoints used to characterize the existing ecological conditions for selected ecosystem services can also be used to evaluate restoration success. A regional, landscape, or seascape focus is needed throughout the risk assessment process, so that restoration efforts play a more prominent role in enhancing ecosystem services. In short, we suggest that practitioners begin with the question of "how can the ecological risk assessment inform the decision on how best to restore the ecosystem?" Integr Environ Assess Manag 2016;12:253-263.

Nonlethal sampling of bird blood and feathers are among the more common ways of estimating the risk of mercury exposure to songbird reproduction. The implicit assumption is that mercury concentrations in blood or feathers of individuals captured in a given area are correlated with mercury concentrations in eggs from the same area. Yet, this assumption is rarely tested. We evaluated mercury concentrations in blood, feathers, and eggs of marsh wrens in wetlands of Great Salt Lake, Utah, and, at two spatial scales, specifically tested the assumption that mercury concentrations in blood and feather samples from birds captured in a defined area were predictive of mercury concentrations in eggs collected in the same area. Mercury concentrations in blood were not correlated with mercury concentrations in eggs collected within the same wetland unit, and were poorly correlated with mercury concentrations in eggs collected at the smaller home range spatial scale of analysis. Moreover, mercury exposure risk, as estimated via tissue concentrations, differed among wetland units depending upon whether blood or egg mercury concentrations were sampled. Mercury concentrations in feathers also were uncorrelated with mercury concentrations in eggs, and were poorly correlated with mercury concentrations in blood. These results demonstrate the potential for contrasting management actions that may be implemented based solely on the specific avian tissue that is sampled, and highlight the importance of developing avian tissues as biomonitoring tools for assessing local risk of mercury exposure to bird reproduction.

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and kidney Cu concentrations were 23- and 6-fold greater, respectively, in SAMW mortalities compared with controls, whereas Cu concentrations in liver were not nearly as increased, suggesting that blood and kidney concentrations may be more useful than liver concentrations for diagnosing Cu toxicosis in wild birds. Based on these findings and other reports of AMW toxicity events in wild birds, we conclude that AMW bodies pose a significant hazard to wildlife that come in contact with them.