I’m convinced that Maine’s sportsmen are among the best people on earth. Last weekend, I helped staff the Maine Audubon booth at the State of Maine Sportsman’s Show in Augusta. Audubon spent the weekend handing out complimentary samples of lead-free sinkers and jigs to passing anglers.

Over the last few decades it has become crystal clear that lead is the top killer of Maine’s loons. Seven times more adult loons are killed by lead poisoning than by getting tangled in discarded monofilament fishing line. It’s not guesswork. The conclusion comes from an autopsy of 450 dead loons.

For the last 10 years, there has been a convergence of attitude between Audubon and sportsmen as both came to realize that they had a strong common interest in Maine’s wildlife. The convergence is so strong that Maine Audubon, a group once perceived to be singularly about birds, partnered with Trout Unlimited and the Maine Department of Inland Fisheries & Wildlife to launch the Brook Trout Pond Survey Project.

Until two years ago, there were many hundreds of Maine ponds that had never been surveyed for brook trout, perhaps the most important game fish species in the state. Brook trout were once abundant throughout the eastern United States. After decades of habitat degradation elsewhere, 90 percent of the country’s remaining population is in Maine. Audubon gleefully co-led the effort to preserve this resource for Maine anglers.

We’ve known for a long time that lead sinkers and jigs are toxic and that we’ve been fishing with poison. In 2002, Maine banned sizes smaller than half an ounce. But loons are big. A bird that can swallow a foot-long perch can certainly gulp down an inch long sinker.

This can happen when the loon catches the one that got away, a fish that still has hook and sinker dangling from its lip. More often, it happens when the loon picks up grit from the lake bottom to aid digestion. Lost fishing gear sinks to the bottom and blends in with the gravel where it is accidentally ingested. When that happens, the loon is dead within two weeks.

There is a bill in the Legislature that would phase out these larger sinkers.

A jig is a fishing lure with the weight built into the hook. This allows it to sink to the proper depth more easily. A lost jig settles to the bottom where the steel hook rusts away. But lead doesn’t rust. Lead can sit on the bottom forever, poisoning loons for generations. That’s the problem with lead. It is soft, easily worked, and corrosion-free.

The Romans made pipes and drinking utensils out of lead. An engineer working for Julius Caesar observed that people with lead pipes were getting sick, but it took the Romans a long time to fully realize they were poisoning themselves. As far back as 200 B.C., a Greek botanist noticed and wrote about the toxic effects of lead on people.

As bad as lead is for humans, it’s worse for loons. Loons must digest fish bones. Gravel in the gizzard grinds up the bones for digestion. It does the same to lead, releasing much more toxicity into the bloodstream than would be experienced by humans or even other waterfowl. We eliminated lead shot in duck hunting because it was slow poison for waterfowl. For loons, ingested lead is fast poison.

Heavy metals are heavy. That’s a useful quality when you want a hook to sink. Many anglers have a stockpile of lead sinkers and jigs, and one shouldn’t casually dismiss their investment in fishing gear. When Maine Audubon opted to take a positive approach to the problem at the Sportsman’s Show, it seemed to be much appreciated.

As I passed out complimentary samples of lead-free sinkers and jigs, I thought I would encounter resistance. Instead, many sportsmen were proud to say that they had already switched to the readily available alternatives, even though it might cost slightly more.

It turns out that Mainers are proud of their loons. The majority of Americans will never know the eerie cry of the loon. That privilege belongs only to residents of the most northern states. Loons are ancient, among the oldest of bird species. Most birds have hollow bones, which makes them lighter and allows them to fly more easily. Loons have solid bones, like their earliest ancestors.

Wabanaki tribes understood loons to be messenger servants to Glooscap, the cultural hero of human creation. Today, the loons are still warning us.

Bob Duchesne serves as a Maine Audubon trustee and vice president of its Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at www.mainebirdingtrail.com. Bob can be reached at duchesne@midmaine.com.