by David Manuwal
Death by lead poisoning is a tragic way of dying and it can be prevented. The article in the January 5, 2022 Hungry Horse News about the death of a swan found at Flathead Lake reminds us that lead poisoning is still a source of mortality among birds.
There are several symptoms of lead poisoning. Neurological signs such as blindness and head tilting may occur or a wing droop or leg paralysis can indicate poisoning. A bird just may not ‘look’ well, sitting quietly with fluffed feathers. A bird may exhibit noticeable weakness, depression, loss of control and coordination of body movements. It may produce frequent runny green droppings, and it may suffer from seizures, muscle tremors and finally death.
Birds obtain lead by eating lead shot from shotgun shells, either incidentally (waterfowl, scavengers such as eagles) or preferentially because it appears like seeds (Mourning Doves). Birds may also consume lead sinkers used in fishing.
History of lead poisoning and what we do about it
The following information was obtained from The Center for Biological Diversity – Birds (biologicaldiversity.org).
Lead poisoning in wild birds was first identified in 1842. In the 1870s, first documented incidents of lead poisoning of waterfowl at hunting sites were found. Here is a list of some important events related to lead.
- 1890’s- The first documented mortality of waterfowl due to lead shot was reported.
- 1959- A major scientific study identified spent lead shot as the source of exposure and widespread hazard for waterfowl.
- 1970 – The Clean Air Act passes congress, giving the Environmental Protection Agency a mandate to identify, and set standards for, harmful pollutants, including lead.
- 1970s – Concerns about lead toxicity from fishing weights for water birds were published.
- 1972 – First nontoxic shot use requirements for limited areas in United States were instituted.
- 1991 – Lead shot is banned for all waterfowl hunting in the entire United States.
- 1992 – Studies were published on the hazards of lead fishing sinkers to loons.
- 1994 – EPA proposes nationwide ban on manufacture, import, processing, and distribution of lead fishing sinkers of a size hazardous to waterfowl — but the regulations are never ratified
- 1997 – Canada implements partial ban on small-sized lead fishing sinkers in national parks and national wildlife areas.
- 1999 – Canada issues ban on lead shot for hunting migratory game birds.
- 2000 – Scientific reports show significant reduction in lead exposure to waterfowl after implementation of 1991 lead shot ban.
- 2007 – California legislature approves the Ridley-Tree Condor Preservation Act, requiring hunters to use nonlead ammunition for hunting big game and coyotes within the California condor’s range in central and Southern California.
- 2007 – The California Fish and Game Commission approves additional hunting regulations that expand the nonlead bullet requirements to include hunting nongame birds and mammals within the condor range.
- 2007 – Number of condor deaths in California confirmed or linked to lead poisoning rises to 15 birds.
- 2008 – The California Fish and Game Commission extends protections of the Ridley-Tree Condor Conservation Act to depredation hunting, the shooting of animals deemed a nuisance or threat.
- 2009 – Lawsuit filed to force management plans on public lands in Arizona to include actions to protect Grand Canyon condors from toxic lead
- 2009 – National Park Service announces plan to eliminate use of lead ammunition and lead fishing tackle in national parks by 2010
- 2009 – The EPA grants citizen petition to ban lead automobile wheel balancing weights — regulations requiring nonlead alternatives to be issued in 2011.
- 2010 – California passes legislation reducing amount of lead that is permissible in plumbing products used to convey or dispense drinking water.
- 2010 – Confirmed lead poisoning death of 15th endangered condor in Arizona since reintroduction program began in 1996, with many more deaths suspected to be from spent lead ammunition.
So we have some legislation that outlaws the use of lead shot in shotgun shells used for waterfowl hunting. However, many states, including Montana, allow hunters to use lead ammunition for upland game birds and big game. Lead shot is readily available in Montana. For example, at Sportsman’s Warehouse in Missoula you can buy a 25 lb. bag of lead shot for $44. There are lots of possibilities for scavengers to pick up lead in carcasses in Montana and other states that have not banned lead ammunition. For waterfowl, the problem is most important in areas where waterfowl hunting has occurred over a long period of time. Lead shot accumulated at the bottom of lakes and ponds and in marshes where hunting has occurred. Lead pellet densities in coastal hunting areas in Louisiana and Texas reach densities of 1,000-3,000 pellets per hectare (= 2.47 acres) Journal of Fish and Wildlife Management (2017) 8 (1): 173–180).
Even though mortality from lead poisoning makes up a relatively small percentage of total bird mortality, we should make every effort to eliminate it, especially because its effects are acute for some key wildlife species such as the California Condor, and a variety of raptors and scavengers that acquire lead from carcasses.
What Can We Do?
We can encourage any attempt by Fish, Wildlife and Parks to ban the use of lead ammunition in all upland game hunting in Montana.