There has been a lot of recent press coverage about the ecotoxicology of lead shot and the benefits of alternatives. Some recent articles are:
Myra E. Finkelstein, Daniel F. Doak, Daniel George, Joe Burnett, Joseph Brandt, Molly Church, Jesse Grantham, and Donald R. Smith. (2012). “Lead poisoning and the deceptive recovery of the critically endangered California condor”. Proceedings of the National Academy of Sciences Published online before print June 25, 2012, doi: 10.1073/pnas.1203141109
Abstract: Endangered species recovery programs seek to restore populations to self-sustaining levels. Nonetheless, many recovering species require continuing management to compensate for persistent threats in their environment. Judging true recovery in the face of this management is often difficult, impeding thorough analysis of the success of conservation programs. We illustrate these challenges with a multidisciplinary study of one of the world’s rarest birds—the California condor (Gymnogyps californianus). California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions. Our results show that condors in California remain chronically exposed to harmful levels of lead; 30% of the annual blood samples collected from condors indicate lead exposure (blood lead ≥ 200 ng/mL) that causes significant subclinical health effects, measured as >60% inhibition of the heme biosynthetic enzyme δ-aminolevulinic acid dehydratase. Furthermore, each year, ∼20% of free-flying birds have blood lead levels (≥450 ng/mL) that indicate the need for clinical intervention to avert morbidity and mortality. Lead isotopic analysis shows that lead-based ammunition is the principle source of lead poisoning in condors. Finally, population models based on condor demographic data show that the condor’s apparent recovery is solely because of intensive ongoing management, with the only hope of achieving true recovery dependent on the elimination or substantial reduction of lead poisoning rates.
News stories covering this study
Joel E. Pagel, Peter B. Sharpe, David K. Garcelon, Annie E. Little, Sharon K. Taylor, Kate R. Faulkner, and Carol S. Gorbics. (2012) “Exposure of Bald Eagles to Lead on the Northern Channel Islands, California.” Journal of Raptor Research 46(2):168-176. doi: http://dx.doi.org/10.3356/JRR-11-18.1
Abstract: Bald Eagles (Haliaeetus leucocephalus) were one of the upper-trophic-level avian predators on the Channel Islands, California, prior to their extirpation by 1960 caused in part by large amounts of DDT discharged into the Southern California Bight. From 2002 to 2006, 61 Bald Eagles were reintroduced onto the northern Channel Islands, as part of a 5-yr feasibility study conducted under the auspices of the Montrose Settlement Restoration Program. In December 2005, a yearling Bald Eagle female was found on Santa Rosa Island with a broken wing and elevated lead levels in her blood of 52.2 ug/dl (0.522 ppm). This incident raised concerns that lead poisoning could be a potential threat to the restoration effort and prompted further investigation. Femurs from five female and two male Bald Eagles reintroduced to the northern Channel Islands were collected postmortem for analyses of lead and other metals. Lead levels detected in femurs of these birds ranged from 0.2 to 55.0 ppm (dry weight). Lead levels in liver were also determined for two of the seven Bald Eagles. Analysis of Bald Eagle movement data from satellite telemetry transmitters suggested that eagles that spent the most time on Santa Rosa Island had the highest lead levels. The results of this study suggested that spent ammunition containing lead found in carrion (offal and entire carcasses) from deer and elk hunting on Santa Rosa Island may have been a primary source of contamination. The on-island hunt program converted to nontoxic bullets in 2007 and ended in late 2011.
Copper Opportunities: Copper Ammo Emerging as the “Bullet of Choice” among Minnesota Deer Hunters (Whitetales)
One favorite tradition among deer hunters is sharing the stories of the hunt following each year’s deer season. This year there are some new and compelling stories emerging from hunters who have switched to copper bullets for deer hunting.