A major change in hunting regulations is due to kick in this fall. All across Canada, lead shot will be banned for the purpose of hunting migratory game birds.

Lead shot has been used in shotgun shells for decades, but in recent years wildlife scientists and managers have grown increasingly aware of its toxic side-effects. Every year in Canada thousands of waterfowl contract lead poisoning from shotgun pellets that have settled in their feeding grounds.

Pellets lodge in the bird's gizzard, where acid and grinding action dissolve the lead. The dissolved metal is then absorbed into the bird's bloodstream, causing lead poisoning. A bird suffering from lead poisoning might not be able to fly or walk. Its wingtips droop, its digestive system breaks down, and it loses weight. A bird suffering from moderate, sub-lethal poisoning might have trouble feeding, mating, nesting, and caring for its young.

Even if the bird doesn't die directly from the lead, it is likely to die from a reduced ability to feed and to avoid predators. The predators, including human hunters, are then in danger too. Eagles have died of lead poisoning after eating waterfowl with lead shot in their bodies.

There's little recorded evidence of lead shot poisoning in the Yukon, but that doesn't mean there isn't a problem, says Jim Hawkings, a biologist with Environment Canada in Whitehorse.

"When birds get poisoned, they usually hide somewhere and die out of sight," he says. "The visible problem is only the tip of the iceberg."

The hazards of lead shot have been recognized internationally for some time. Denmark and The Netherlands have banned lead shot for all hunting. The United States and Norway have banned it for waterfowl hunting, and the United States is considering broadening the ban. A number of other countries have some form of restriction on the use of lead shot, and Australia is considering a national ban.

In 1991, Canada joined many other countries in creating "non-toxic shot hunting zones" where lead shot is not permitted for hunting migratory game birds. In 1995, British Columbia banned the use of lead shot in all waterfowl hunting. Last year, it was banned in National Wildlife Areas and non-toxic shot hunting zones. This year, the ban will extend across Canada.

The ban doesn't mean an end to hunting by shotgun. Steel and bismuth shot are currently available, and manufacturers are experimenting with other materials.

"Bismuth is probably the best alternative," says Hawkings. "It's similar to lead but non-toxic. It's more expensive, but the price will probably come down as more of it is produced."

Lead shot from shotguns isn't the only source of lead poisoning in birds. Lead sinkers and jigs, lost from fishing lines, are equally disastrous. According to one estimate, 500 tonnes of lead sinkers and jigs are lost in Canadian waters each year.

Sinkers and jigs are particularly dangerous for diving birds like loons. Just one sinker or jig is enough to kill a bird. In eastern North America, up to half of the Common Loons found dead have died from eating a lead sinker or jig.

Lead sinkers have been banned in Great Britain since 1987. North America has been slower to deal with the problem, but the United States is currently planning a similar ban. In the fall of 1996, Canada banned the use of lead sinkers and jigs in all national parks and national wildlife areas.

There are even more alternatives to lead in fishing than in hunting. Sinkers can be made from tin, bismuth, steel, special putty, and a number of other materials that do not poison birds.

For more information about lead in the environment and alternatives to lead shot and sinkers, contact Environment Canada in Whitehorse. Both Environment Canada and the Yukon Department of Renewable Resources have free brochures explaining the new hunting and fishing regulations, and outlining the adjustments required to use steel or bismuth shot.