Molly Church's master's research on Condors contributed to the ban of lead ammunition in California's Central Valley.

Molly Church, a TSR&TP alumna from UC Santa Cruz and current doctoral student in Veterinary Medicine at the University of Pennsylvania, talked about her work studying lead exposure in condors. She began with the history of condors in California. Condors have existed as a species for about 40,000 years and they have gone through two periods of major decline. They are extremely sensitive to negative impacts. Condors live until age 50 and reproduce every other year.

In 1982 there were about 24 condors left in California and of those, 9 remained in the wild. In 1987, all condors were placed in captivity. Since condors were re-released into the wild in the early 1990s, lead poisoning has been a major cause of decline. Twelve condors have died from lead poisoning, and over 30 have gone through chelation therapy to remove lead.

Church and her colleagues at UC Santa Cruz researched the source of the lead affecting condors. Sources can include soil and vegetation near industrial sites, deteriorating paint, lead sinkers, and ammunition. Lead bullets fragment throughout the meat when an animal is shot. Condors are scavengers that feed on hunted game, and they have been found with lead in their gastro-intestinal tracts.

The ratio of lead isotopes varies depending on the source of the lead. The technique of looking at lead isotope ratios has been used to determine sources of lead poisoning in children for years. Church's group used this technique with condors. They collected blood samples from condors that had yet to be released and from condors that had been in the wild for a while. They also collected samples from deer, calves and sea lions to represent the natural low lead diet. The group collected shotgun and rifle ammunition for analysis as well.

Church hypothesized that the source of lead in condors was either the low background lead diet or the high ammunition based lead. Twenty of the 26 condors sampled fell within the model and supported the hypothesis. Lead levels in free flying condors were substantially higher than pre-released birds.

Once Church's group had shown that ammunition is the most probable source of lead that was poisoning condors, they were able to contribute to a change in California hunting laws. This change required a true collaborative effort and perfect timing. The effort involved the centers for wildlife, media coverage, lobbying state legislators, the fish and game commission, the governor, and a statement of scientific agreement from several scientists. Timing was important too: "California Assembly member Pedro Nava had already introduced a bill twice before 2007. The Fish and Game Commission were due for a review of hunting policy in 2007, and our paper was published at the end of 2006 and had started attracting the attention of some people," explained Church.

"The NRA didn't agree with our results," said Church. They rebutted the results of Church's paper and some of them became regular fixtures at the public hearings. Despite setbacks, the legislation to ban lead ammunition for hunting in California's Central Valley was signed into law by Governor Schwarzenegger in October 2007.

"There are still numerous projects to work on," said Church. One important project is to continue monitoring blood lead levels in condors to see if the legislation has a beneficial effect. Another UCSC student is working on using feathers to show lead levels and looking at enzyme activity to assess subclinical effects.

Church thanked the many people who worked with her on the research, "And of course UC Toxics for funding my work in the first place."

Table of Contents   Previous Article   Next Article