An effort is underway to replace a significant source of lead in the environment— hunting ammunition.

Lead is a known toxic substance with serious health effects for humans and wildlife alike, including neurological damage, retarded growth and cognitive development, sensory loss, behavioral impacts, and death. Recognition of the dangers from lead has brought about its removal from paint, gasoline, food containers, plumbing, inks, toys, and other sources of exposure.

The hazards of lead ammunition to waterfowl and other wildlife have been documented in recent years. In North America, loons have been seriously affected due to their habit of ingesting lead shot, apparently for use as grit. These and other birds are also impacted by lead deposition from the atmosphere, which enters the food chain and bio-accumulates in longer-lived species. Although not always a direct source of mortality, lead weakens birds and leaves them susceptible to other illness, and reproductive failure.

New York and other jurisdictions have restricted the use of lead fishing sinkers and tackle, and lead shot for hunting waterfowl has been banned nationwide, due to these threats. These activities continue successfully, using less toxic materials such as bismuth or copper. Studies indicate that lead restrictions have been successful in reducing lead levels in these birds.

However, lead is still the material of choice in ammunition for upland hunting—for deer, game birds and small game. Use of lead shot, slugs and rifle bullets remains widespread for these purposes. The ammunition poses a continuing danger to birds such as doves and pigeons that pick up shot, and also to scavengers that feed on wounded and unretrieved prey, or discarded animals or entrails.

Data show that lead exposure for eagles, vultures and other scavengers is on the rise, especially during hunting seasons. For example, a study of Ravens in the Yellowstone region showed that 50% of the birds had elevated lead levels during hunting seasons when entrails and other offal were available. This compares with 3% having high lead levels during non-hunting periods. Similarly, comparison of lead levels in Bald and Golden Eagles from non-hunting to hunting periods showed a significant increase. Researchers stated “the magnitude of lead in the blood of many eagles is extremely high and likely results in the death of some individuals.”

Lead ingestion was a principal cause of recorded death in wild California condors prior to the mid-1980s when the population was brought into captivity. It remains a serious problem, and the California legislature has banned the use of lead ammunition in the condors’ range.

Investigation of the specific isotopes of lead found in birds points to lead ammunition as the cause of poisoning rather than other possible sources.

The threats from lead ammunition do not end with birds and wildlife. There is increasing evidence that humans consuming wild game ingest lead fragments in venison and other meat. A 2008 (NYSOA Conservation Column...Continued from page 9) study of over 700 North Dakotans by the Centers for Disease Control showed elevated blood lead levels in those who consumed game. This led the state health department to issue an advisory to food pantries to not distribute donated ground venison because of the discovery of contamination with lead fragments. In addition, the state recommended that pregnant women and children under six not eat any venison harvested with lead bullets, and cautioned all others about potential exposure to lead. Other states have taken similar actions.

Clearly a problem exists with the continuing use of lead ammunition. It would be hoped that hunters would recognize the dangers to their own health and that of their families, as well as the serious impacts on birds and other wildlife. Providing information on the overwhelming evidence at hand should help convince users of lead shot and bullets to switch to less toxic alternatives.

As Professor Ian Newton said in summarizing the findings of The Peregrine Fund’s 2008 conference, Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans, ”There may be no need for advocacy here: just the targeted distribution of unequivocal scientific findings by appropriate messengers.” NYSOA, its member organizations, and individual members and other birders can be among those messengers. However, we need to be aware and prepared to move ahead with efforts to mitigate this threat through legislation and regulation if self-policing is not effective. It is time to get this insidious threat to our birds and ourselves out of the environment.

(Proceedings of the above-mentioned conference provide a wealth of information on this issue, and can be accessed at www.peregrinefund.org/lead_conference.)

Read Andy's update, published in the October 2010 issue of NY Birders