The Challenge: Neonicotinoid pesticides act as agonists of nicotinic acetylcholine receptors (nAChRs) and are designed to be lethal to insects while theoretically posing little to no threat to vertebrates. The perceived safety of neonicotinoids has led to a sharp increase in their use in the United States and globally, since they were first introduced in 1994. The use of the neonicotinoid imidacloprid in the United States has increased 166% since 2009, from 0.75 to roughly 2 million pounds, and its use as seed treatment represents approximately 56% of total annual usage. Although neonicotinoids are designed to be selectively toxic to invertebrates, effects on other organisms are being reported. However, toxicity information on birds is particularly limited. Birds are primarily exposed to neonicotinoids orally (feeding, preening), by inhalation, or dermally depending on whether the pesticide is applied by aerial spraying or as a seed coating.
The Challenge: Endocrine active chemicals (EAC) are known to interfere with hormonally regulated physiological processes, thereby affecting signaling in the hypothalamic-pituitary-gonadal-liver (HPGL) axis and commonly resulting in reproductive dysfunction. Computational models that relate hormonal and genomic biomarkers within the HPGL axis to the reproductive cycle and ecologically relevant endpoints have been developed for fish; however, no similar model is available for birds. These models are very useful for evaluating how EAC-induced changes in physiological systems enhance or inhibit embryonic development, reproduction, and growth.
The Challenge: Wild birds are exposed throughout their lives to natural and synthetic chemicals that are present in the environment, many of which interfere with the animal’s physiological and developmental systems. Relative concentrations, routes, frequency, and the environment in which chemical exposure occurs will determine to a large extent the bird’s response. Well-designed avian field studies conducted on site are expensive, both in terms of personnel and funding. In order to address specific field exposures and/or focus on variables of particular concern, pen studies can be conducted on a smaller scale. The Japanese quail (Coturnix japonica, JQ) has been used as a model for gallinaceous birds in research because it exhibits a short generation time of 53-74 days and all stages of its development can be maintained and tested in captivity under controlled laboratory pen conditions. As we move towards minimizing the numbers of animals used for research, the role of the JQ as an appropriate model for avian wildlife in ecotoxicological studies is being redefined.
The Challenge: Mercury is a highly toxic element found throughout our environment. Although it occurs naturally in some environments, human industrial pollution has greatly increased the amount of mercury and the range of environments in which mercury is found. Recent studies have confirmed clear differences in the sensitivity of various bird species to methylmercury. Because the causes of these differences are unknown, prediction of mercury sensitivity is difficult in birds that have not or cannot be studied in the lab. Therefore, a method is needed that can predict sensitivity to mercury in poorly studied birds and can help identify susceptible populations.
The Challenge: Short-Chain Chlorinated Paraffins (SCCPs) are complex technical mixtures of polychlorinated n-alkanes used in lubricants and coolants in metalworking, as flame retardants, and in paints, adhesives, sealants, textiles and polymeric materials, plastics and rubber. SCCPs are of concern because they are globally transported, bioaccumulate in wildlife and humans, and are environmentally persistent. Their toxicity has been demonstrated in multiple species and their presence has been detected in wild birds and their eggs far from primary manufacturing centers. However, few controlled studies have been conducted to determine the potential hazard and risk that SCCPs pose to free-ranging birds.
The Challenge: The use of flame retardants (FRs) as additives in a variety of consumer use products, including plastics, textiles, and electronics, is projected to continue and increase for the foreseeable future. Because of unanticipated environmental problems, some FRs have either been banned, restricted, or are being phased-out and replaced by other new and presumably safer FRs. Regrettably, many of these alternative FRs are found to bioaccumulate in wildlife tissues, including in bird eggs, suggesting exposure through maternal deposition. However, few data are available on the potential adverse effects in exposed animals.
The Challenge: Neonicotinoids are now the most widely applied class of insecticides in the United States, and are predominantly used in the form of seed treatments. Compared to invertebrates, neonicotinoids are less toxic to wildlife, although genotoxic, cytotoxic, immunological, behavioral and reproductive effects have been reported in studies with birds. At present, little is known about the pharmacokinetics (absorption, distribution, metabolism and excretion) of these pesticides in birds, which can dictate and affect the timecourse of their toxicity. Such information will greatly assist in evaluating the hazard and risk of neonicotinoid seed coatings to wild birds.
The Challenge: As a rule, plants and animals contain lower concentrations of lead than are present in soils that support them. Lead does not biomagnify along trophic levels in ecosystems but instead remains relatively immobile in soil. The exposure of wildlife to soil lead depends mainly on the incidental ingestion of soil. The native earthworm, Eisenoides lonnbergi, is anomalous in its ability to concentrate lead from acidic soils. This raises the question what makes this earthworm so different from other organisms that have been studied. As a rule, plants and animals contain lower concentrations of lead than are present in soils that support them. Lead does not biomagnify along trophic levels in ecosystems but instead remains relatively immobile in soil. The exposure of wildlife to soil lead depends mainly on the incidental ingestion of soil. The native earthworm, Eisenoides lonnbergi, is anomalous in its ability to concentrate lead from acidic soils. This raises the question what makes this earthworm so different from other organisms that have been studied.
Although there are ways of developing causal relationships between stressors and aquatic community responses without experimentation; some argue that experimental manipulation under controlled conditions is both critical and necessary to establish causation. Single species toxicity tests are the gold standard for developing toxicant biological response relationships however these tests are criticized for their lack of environmental realism and relevance to ecosystems.
The Challenge: Black-tailed prairie dogs are considered a keystone species for the prairie habitat. Many avian species are associated with black-tailed prairie dogs (Cynomys ludovicianus) in winter. Raptors feed on prairie dogs and non-raptor avian species forage within prairie dog colonies. However prairie dogs are also considered agricultural pests. The first generation anticoagulant rodenticide Rozol Prairie Dog Bait (chlorophacinone, active ingredient) is registered for control of prairie dogs during winter. Information is needed to determine if operational applications of Rozol at prairie dog colonies result in adverse effects to birds and other non-target wildlife.
Human dimensions in the context of natural resource management refers to the ways humans value natural resources, resource management preferences, and how humans affect or are affected by natural resource management decisions. Natural resource management and policy decisionmaking require incorporation of sound biological, social, and economic science. SEA scientists use tools, research methods, and training to support managers in the creation and revision of Federal land and water management plans.
The Challenge: Agricultural, industrial and urban activities have had major effects on waterbirds in Chesapeake and Delaware Bays. Some legacy pollutants (PCBs, organochlorine pesticides, flame retardants, metals) pose a potential threat to wildlife in some locations. Pharmaceuticals, personal care products, and endocrine disrupting compounds have been detected in water and fish tissue, yet knowledge of effects on wildlife is limited. This is the first study to examine bioaccumulation of pharmaceuticals and their fate in the water-fish-osprey food chain.