This is the opening talk of the session titled "Impacts of Citizen Science," delivered on day two of the Citizen Science Toolkit Conference at the Cornell Lab of Ornithology in Ithaca, New York on June 20-23, 2007. Stephen Baillie, Director of Populations Research at the British Trust for Ornithology (BTO), shares examples of how research and monitoring undertaken by the BTO, based largely on volunteer surveys, has had an impact on conservation and environment policy in the U.K. Specifically, Baillie discusses a project related to the conservation of farmland birds and work on Avian Influenza.