This review is focused on the effects of contaminants on wildlife and the potential for using wildlife as sentinels for human and environmental health. Some wildlife are permanent residents of the boreal forest encompassing the oil sands region, while many others are seasonal residents using this area as breeding grounds (i.e., migratory birds), both providing the potential for ongoing research into the biological effects of contaminants from oil sands activities. Wildlife species may act as sentinels, or early warning systems, providing insight into the effects of contaminants on environmental and even human health. In the oil sands, both field and laboratory studies have used wildlife as bioindicators and/or sentinels of ecosystem health. The great majority of this research has focused on aquatic ecosystems and organisms. Fish exposed to oil sands process affected water (OSPW), or water plus sediments from tailings ponds, and water from wetlands receiving oil sands effluents, have shown a range of detrimental physiological effects including increased detoxification activity by the liver, alterations in growth, hormonal disruption, abnormalities in hematological variables, pathologic changes in the gills, and increased mortality rates relative to fish from reference sites. Studies indicate that mature, reclaimed wetlands in the oil sands, those seven years or older, can support viable populations of locally important amphibians, whereas the younger wetlands retain toxic compounds which cause detrimental health effects such as decreased survival, delayed development, and increased rates of malformation. Most research on birds has also focused on aquatic toxicology. Growth alterations (smaller skeletal size and body mass) have been reported in waterfowl raised on wetlands receiving oil sands effluent. Migrating waterfowl are at risk of landing on tailings ponds with floating bitumen, despite considerable efforts to design and deploy deterrent systems, and mass mortalities have resulted. Increased levels of mercury (Hg) in the eggs of water birds, and a positive correlation between Hg and naphthenic acid (NA) concentrations, suggests a common source of exposure for birds nesting on lakes that receive water from the Athabasca River downstream from the oil sands region. On the mine lease areas, reclaimed wetlands have in most years supported active populations of tree swallows during the breeding period and rearing of the offspring. However, stochastic events such as many days of cold, wet weather can cause severe stress resulting in high mortality rates. Studies of risk to mammals from tailings pond water suggest that terrestrial wildlife is unlikely to develop acute toxicity from NA exposure, although negative health effects may occur from repeated, or long-term exposures. We have identified a conspicuous gap in knowledge related to effects of airborne contaminants on any species. Birds may prove especially valuable as sentinels because of the unique anatomy and physiology of their respiratory system (birds are more sensitive to airborne contaminants than mammals of similar size). As well, as pointed out in the report from the Royal Society of Canada, \"quantifying these emissions is notoriously difficult and the data available in the National Pollutant Release Inventory on this subject do not provide enough detail to know what sources have been estimated nor how valid the numbers are\"; and, \"the subject of non-point (fugitive) emissions of air contaminants from mines and tailings ponds is highly uncertain and currently available estimates are unlikely to be entirely valid\". One approach to better understand the effects of emissions on wildlife (and warm-blooded animals in general) could be through research on birds of prey (raptors). Raptors such as the American kestrel (Falco sparverius) could provide integrated insight into food web, as well as air borne exposure to environmental contaminants over time. Together with concurrent studies of their prey species, such as small mammals inhabiting reclaimed terrestrial areas, this type of work has the possibility of generating information relevant to the health of a range of animals in that ecosystem. Other studies of wildlife sentinels of ecosystem health could be based on herbivores. Domestic sheep and goats could serve as surrogates for caribou, moose and other ungulates naturally found in this region, for assessing health effects from deposition and accumulation of particulate air contaminants on vegetation. A final option would be to use small mammals such as mice and voles as sentinels of ecosystem health. Such species reflect the quality and quantity of local vegetation, readily populate any available area and serve as food for mammalian and avian predators. For the oil sands as well as other petroleum producing regions, major emissions of interest are volatile organic compounds, hydrogen sulfide, sulphur dioxide, nitrogen dioxide, ozone and particulate matter, whereas aquatic contaminants related to the petrochemical industry are polycyclic aromatic hydrocarbons, naphthenic acids, sulphate ions, ammonia and trace metals. Once in the environment, complex interactions among contaminants and substrates along with inherent chemical characteristics will determine the fate of these compounds. Extraction and production of bitumen from the oil sands produces compounds of environmental concern in the form of emissions perceived to pose risks to flora and fauna in local and downwind regions, and in the form of great volumes of liquid tailings. Research on wildlife species, used as either monitors, or indicator species, can provide early warning and predictive information regarding exposure and effects of contaminants from oil sands activities that would complement the huge ongoing investment into air and water monitoring systems.Appendix 2 (added in Jul 2013) provides a summary of findings from a 2012 study of tree swallows with a focus on air-borne compounds, using these insectivores as sentinels, as described above.