Temporal and spatial distribution of mercury and methylmercury source types, transfer and impact in the North American arctic and sub-arctic food web using seabird eggs and feathers Mercury appears to be increasing in the environment, world-wide. Scientists from North America and Europe will use seabird eggs and feathers to track sources of mercury and assess regional differences in mercury in the western Arctic by applying highly sensitive, newly developed analytical techniques. Eggs and feathers archived from past collections will be used to study changes from the past.