How much do we love loons — really?

The loons who ply our Northwoods lakes are right now down south on their wintering grounds. Before too long, maybe as little as 70 days from now, they’ll be back, provided the ice has gone out. For those of us who are anglers, now is a good time to rethink (if we haven’t already) the jigs and split shot and other tackle items we use.

Lead is deadly to loons. They pick up pebbles from the lake bottom to help them grind food in their gizzard. If one of those “pebbles” happens to be a piece of lead, that loon in doomed. The acid and grinding action in the gizzard dissolve some of the lead, which passes into the bloodstream, organs and the nervous system. Even the smallest sinker will deliver a lethal dose.

How often do loons die from lead poisoning? More often than you might think. Scientists have extensively studied this subject. A 25-year study by Maine Audubon ranked lead sinkers and lead-head jigs as the largest among 13 causes of mortality in loons found dead and autopsied:  97 of 352 adults, or 28%. In New Hampshire, the Loon Preservation Committee found that 48.6% of dead adults collected from 1989 to 2012 died by poisoning from lead fishing tackle.

In Michigan Τom Cooley, pathologist at the DNR wildlife disease laboratory, examined 376 dead loons over 27 years and found that 16% died from lead poisoning, the third-largest cause of loon mortality. Limited research by the Minnesota Pollution Control Agency has linked 12 percent of loon deaths to lead poisoning, among those with known causes of death.

Carrol Henderson, a board member of the National Loon Center in Crosslake, Minnesota, calls the loss of lead tackle by anglers each year a “cumulative contamination” of lake bottoms. During his career leading the Minnesota Nongame Wildlife Program, staff members received results of necropsies performed on loons found dead. “We would have the centers doing the work for us send us bags with the pebbles that were found in the gizzard of each of those loons,” he recalls. “In some of those packets there would be two or three dozen little pebbles a little bigger than BB size, and then sometimes there would be a split shot or a lead jig, which would be the reason the loon died.

Nontoxic alternatives to lead are available for some kinds of tackle, but unfortunately not for others. Water Gremlin offers tin split shot. Northland Tackle, at least until recently, offered Nature Jigs in an alloy of tin and bismuth. I now use those products exclusively. I wish it were earlier to find safe alternatives for items such as jigheads for swim baits and tube jigs. In any case, if we care about loons as much as we say, it’s time to consign as much or our lead tackle as possible to a recycling center.( Photo by Linda Grenzer. X-ray taken at Raptor Education Center, Antigo, Wisconsin.)