Lead Poisoning

We Regulate Lead Paint,And Outlaw Leaded Fuel

But, We Hunt with Lead Ammunition and Fish with Lead Sinkers and Lures

Lead Toxicity

• Known since 2nd Century BC• Damages cell membranes• Disrupts enzyme production– Interfere with Vitamin D and heme production

• Blocks NMDA receptors which bind glutamate in neurons

• Effects organs– Kidneys, heart, gonads

Some Exposure in Hunters

• Hunters that eat more venison have more lead in blood, but very low levels typically

CDC and North Dakota Dept of Health, 2008 Study of hunters

Some Steps Taken

• Lead shot banded from waterfowl hunting – US, 1991– Canada, 1997

• Lead in fishing lures/weights banned selectively – 13 Loon lakes in WA, May 2011

• National ban on lead denied 2010 by EPA– Petition to amend Toxic Substances Control Act of 1976 by

CBD, ABC, led by Michael Fry claimed• 20 million birds / year killed• 3,000 tons of lead on hunting grounds / year• 4,000 tons in fresh water

Loons, Lead, Stones

Loon Deaths

Swans in the Northwest

• Since 1999, 2300 swans (mostly Trumpeter and some Tundra) died from ingesting lead shot in BC and Whatcom County, WA www.swansociety.org

California Condor and other Scavengers

Photo by Sue Haig

(Lambertucci et al. 2011)

Lead Shot Ban Does Not Protect Bald and Golden Eagles

Kramer and Redig 1997

Eagles in Pacific Northwest Get Lead from Scavenging, (e.g. coyote)

Stauber et al. 2010

Exposure Particularly Bad in Winter, not during Autumn Hunting

(Craighead and Bedrosian 2008)

In Wyoming, Ravens Exposed to Lead in Autumn

Raven Exposure is Related to Hunting Season

California Condor: A Rare Species

• Captive breeding and release has brought the condor from 22 birds and extirpation from the wild to 300+ birds and 150+ wild birds in two decades– 4 breeding facilities– Releases southern

and central California, Arizona, Baja in Mexico

• Condors survive in the wild only through constant and costly human assistance and intervention

Figure from Wallace et al. 2007 California Condor Master Plan

(Walters et al. 2010)

Lead is Major Problem for CondorsDuring Hunting Season

Chelation

Molecules with negative charge bind positively charged lead, form non-toxic chelate that is excreted

(Borkowski 1997)

Example from Snapping Turtle

Banning Lead Ammunition in the Range of the California Condor in California (2008)

Kelly et al. 2011

Less Lead in Scavengers After Ban

Not Fully Protecting Condors: 2010 first chick born in Pinnacles in 100 years has to be chelated (Audubon California)

In Arizona, when Condors scavenge on North Kaibab, they encounter and ingest lots of lead

Green et al. 2008 3 Birds Died in 2008

Condors Go North During Hunting Season

Movements into high lead, north Kaibab, is expected to kill Condors

HUMANS

Hunting Good, Lead Bad

• Conclusion: condors suffer lead poisoning from ingestion of spent ammunition sufficiently frequently to raise mortality rates well above those required for sustainability

• Conclusion: Hunters are the dominant predators within condor’s range and are important source of food for condors

• Recommendation: Eliminating lead threat should not be accomplished by reduction in hunting, but by replacement of lead ammunition with non-lead alternatives. Hunters should be made aware of their importance to condors

Photo by Anna Fuentes

(Walters et al. 2010)

Lead Is Not the Only Problem • Conclusions: Successful nesting in southern California is contingent

upon intensive nest monitoring because of the microtrash problem

• Most promising approaches to problem are cleaning up trash, returning offending adults to captivity for aversive training, promoting more natural foraging patterns– Latter may not reduce feeding of microtrash by breeders with tradition of such

behavior

Recommendation: Continue to clean up trash, conduct experiments with aversive training

Photo courtesy of USFWS

References• Pokras, M., Kneeland, M., Ludii, A., Golden, E, Major, A., Miconi, R., and R. H. Poppenga. 2009.

Lead objects ingested by common loons in New England. Northeastern Naturalist 16:177-182.• Green, R. E., Hunt, W. G., Parish, C. N., and I. Newton. 2008. Effetiveness of action to reduce

exposure of free-ranging California Condors in Arizona and Utah to lead from spent ammunition. PLOS One 3:e4022.

• Craighead, D. and B. Bedrosian. 2008. Blood lead levels of common ravens with access to big-game offal. J. Wildlife Management 72:240-245.

• Kramer, J. L. and P. T. Redig. 1997. Sixteen years of lead poisoning in eagles, 1980-95: an epizootiologic view. J. Raptor Research 31:327-332.

• Borkowski, R. 1997. Lead poisoning and intestinal perforations in a snapping turtle due to fishing gear ingestion. J. Zoo and Wildlife Medicine 28:109-113.

• Lambertucci, S. A., Donazar, J. A., Huertas, A. D., Jimenez, B., Saez, M., Sanchez-Zapata, J. A., and Hiraldo, F. 2011. Widening the problem of lead poisoning to a South-American top scavenger: lead concentrations in feathers of wild Andean condors. Biological Conservation 144:1464-1471.

• Kelly, T. R., Bloom, P. H., Torres, S. G., Hernandez, Y. Z., Poppenga, R. H., Boyce, W. M., and C. K. Johnson. 2011. Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures. PLOS One 6:e17656.

• Walters, J. R., Derrickson, S. R., Fry, D. M., Haig, S. M., Marzluff, J. M., and J. M. Wunderle. 2010. Status of the California Condor and efforts to achieve its recovery. Auk 127:969-1001.

• Stauber, E., Finch, N., Talcott, P. A., and J. M. Gay. 2010. Lead poisoning of bald and golden eagels in the US inland Pacific northwest region—an 18-year retrospective study: 1991-2008. J. Avian Medicine and Surgery 24:279-287.