In this presentation, Dr. Doug Tozer, Director, Waterbirds and Wetlands, Birds Canada, will overview information from a remarkable 35,000 breeding attempts by Common Loon pairs across the country, collected by over 4000 volunteers. The talk will focus on what these carefully-collected and hard-earned data can tell us about what might be behind the declines and what we should do next to best conserve this impressive symbol of pristine wilderness. Several decades of volunteer data were used from Canadian Lakes Loon Survey to document and help explain mysterious declines over the years in the number of Common Loon babies raised to independence (i.e., loon “productivity”). The analysis shows that Common Loon productivity has significantly decreased across most of southern Canada over the past several decades. Of course, the “million-dollar” question is why is loon productivity declining?