Aquatic bird eggs are being collected for contaminants analysis. Egg collections in the Peace-Athabasca Delta area support Parks Canada’s activities at Wood Buffalo National Park and the multi-stakeholder Peace-Athabasca Ecosystem Monitoring Program. This monitoring activity employs repeated censuses of birds and builds on initial egg collections made in 2009 from Egg Island (Lake Athabasca) and Wood Buffalo National Park, with the goal of evaluating contaminant burdens, contaminant sources and changes in sources through time. Egg samples are collected from colonial waterbirds California Gulls (Larus californicus), Herring Gulls (Larus argentatus), Ring-billed Gulls (Larus delawarensis), Caspian Terns (Hydroprogne caspia) and Common Terns (Sterna hirundo) and insectivorous birds Bank Swallows (Riparia riparia), Cliff Swallows (Petrochelidon pyrrhonota) and Tree Swallows (Tachycineta bicolor) to monitor health and contaminant levels of aquatic and terrestrial birds in the oil sands region and in reference areas. The samples collected are analysed for oil sands-related contaminants including polycyclic aromatic hydrocarbons (PAHs) and metals such as mercury (Hg) and arsenic (As).