From this story on boston.com:
A New Hampshire group working to preserve the state's threatened loon population says a dozen of the birds died last year after ingesting lead from fishing tackle. The Loon Preservation Committee said seven loons died from lead sinkers and jigs that are currently banned under state law, but five other deaths were linked to longer lead jigs that remain legal under state law. The nonprofit group's executive director, Harry Vogel, told the Concord Monitor that the current law doesn't go far enough to protect loons, which have been declared a threatened species in New Hampshire. Vogel says there were about twice as many loon deaths in 2010 than in previous years. There are an estimated 275 pairs of loons in the state. Sport fishermen have opposed stronger limits on lead in tackle.