Mortality Threats to Birds - Lead

The Problem

California Expands Lead Ban to Further Protect Endangered Condors
Lead Ban Victory in California for Condors

California Condor: Photo FWS

Despite a 1991 federal ban on lead shot for waterfowl hunting, lead poisoning continues to be a problem for birds through the hundreds of tons of lead deposited in the environment annually by upland game hunting, fishing, and clay pigeon shooting. Waterfowl, waders, upland game birds and passerines may eat lead shotgun pellets and split shot sinkers mistaking them for grain or grit. Additionally, raptors may become poisoned by ingesting lead embedded in prey carcasses. Once digested and absorbed into the blood, as little as a single pellet can be lethal, but sublethal lead levels can also compromise health and cause neurological dysfunction.

Lead is inexpensive and, because of its density, is preferred by hunters over steel for accuracy. Lead’s malleability allows anglers to attach sinkers to fishing line with ease, making it a fishing favorite. But the price for such recreational convenience is high. Research in the Northeast suggests that lead is the leading cause of death in adult loons, and secondary lead poisoning has been documented in an array of raptors, especially Bald Eagles, Golden Eagles, California Condors, and accipiters (in 2000, five California Condors died of lead poisoning after feeding on deer carcasses containing lead bullets). Lead poisoning in Trumpeter Swans has also been widely documented in the West.

Recently, an new lead threat has emerged: paint peeling from federal buildings on Midway Atoll National Wildlife Refuge is threatening the world's largest breeding colony of Laysan Albatrosses. Read more about this issue here.

The Solution

Recognizing the harm lead was causing swans, diving birds, and wading birds, Great Britain banned the use of lead sinkers weighing less than one ounce in 1987. The ban was implemented after voluntary efforts were ineffective. In 1997, Canada prohibited the use of lead sinkers and jigs weighing less than 50 grams (1.76 oz.) in all of its national parks and wildlife areas. To date, no federal U.S. law has been implemented to ban or limit lead sinker use, though some states are actively addressing the problem by banning the sale or use of certain lead sinkers and jigs.

Efforts to phase out lead shot began in the 1970s, but a nationwide ban on lead shot for all waterfowl hunting was not implemented until 1991. Lead shot may still be used for certain upland game species. Canada instituted a complete ban on the use of lead shot in 1999, after initially banning its use near bodies of water and on national wildlife areas.

Trumpeter Swan : Photo FWS

A study by the Illinois Natural History Survey suggests that the ban on the use of lead shot for waterfowl hunting has had remarkable success in preventing the premature deaths of millions of waterfowl from lead poisoning. The report, published in the Journal of Wildlife Management, examined thousands of ducks harvested in the Mississippi Flyway during the 1996 and 1997 waterfowl seasons, the fifth and sixth seasons after the 1991 ban on lead shot. It found only 1.1 percent of examined ducks showed evidence of being shot with lead, and concluded that by significantly reducing lead shot ingestion in water fowl, the ban prevented the lead poisoning deaths of approximately 1.4 million ducks in the 1997 fall flight of 90 million ducks. Extending this ban to all hunting would lead to further dramatic declines in bird deaths from lead poisoning.

Until such a ban is forthcoming, HawkWatch International has launched its Wildlife Lead Poisoning Reduction Program (WLPRP), an outreach effort designed to inform outdoor enthusiasts of the unintended consequences to wildlife of lead use, and to encourage the use of alternative, non-toxic ammunition and tackle.

What You Can Do

Hunters now have a choice of eight types of non-toxic shot for hunting. Although the federal ban on lead does not stretch to upland game hunting, making the change to alternative forms of shot will save millions of birds from poisoning.

Lead-free fishing sinkers and jigs are also widely available, and where used will prevent the needless deaths of waterfowl such as Trumeter Swans, ducks, and geese.