Spatiotemporal Patterns and Risk Factors for Lead Exposure in Endangered California Condors during 15 Years of Reintroduction

Kelly, T. Ross; Grantham, Jesse; George, Daniel; Welch, Alacia; Brandt, Joseph; Burnett, L. Joseph; Sorenson, Kelly J.; Johnson, Matthew; Poppenga, Robert H.; Moen, David; Rasico, James; Rivers, James W.; Battistone, Carie; Johnson, Christine K.

doi:10.1111/cobi.12342

Cited by 34 publications

(57 citation statements)

References 15 publications

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“…Lead analysis was conducted on-site using a portable lead analyzer (Lead Care Blood Lead Testing System, ESA Inc., Chelmsford, MA), which enabled assessment of the need for clinical intervention consisting of hospitalization, chelation therapy, and occasionally surgical management (Hall et al, 2007). Blood samples were also shipped to multiple commercial laboratories (Antech Diagnostics, Irvine, CA; Louisiana Animal Disease Diagnostic Laboratory (LADDL), Baton Rouge, LA; California Animal Health and Food Safety Laboratory (CAHFS), University of California, Davis, CA) for lead analysis as previously described (Kelly et al, 2014).…”

Section: Data Sourcesmentioning

confidence: 99%

“…Over the study period, the annual prevalence of elevated lead exposure (i.e., percentage of sampled condors with blood lead ≥10 μg/dL in a given year) ranged from 62 to 91% (median = 75%). During the post-ban period, the annual prevalence of elevated lead exposure ranged from 79% to 87% (Kelly et al, 2014). Over time, as reintroduced condors have matured and become more experienced in the wild, they have been detected less frequently near managed release sites, and become less reliant on food provisions (Kelly et al, 2014).…”

Section: Threats To Survivalmentioning

confidence: 99%

“…During the post-ban period, the annual prevalence of elevated lead exposure ranged from 79% to 87% (Kelly et al, 2014). Over time, as reintroduced condors have matured and become more experienced in the wild, they have been detected less frequently near managed release sites, and become less reliant on food provisions (Kelly et al, 2014). These shifts toward greater natural foraging, which were most pronounced during the post-ban period, are associated with a higher probability of encountering carrion containing lead ammunition and therefore, a heightened risk of lead poisoning (Kelly et al, 2014).…”

Section: Threats To Survivalmentioning

confidence: 99%

“…In addition, California condors have been regularly provisioned with food at the release sites since reintroductions began, primarily as a means to transition young captive-reared juveniles to the wild and capture individuals for routine management and monitoring (Walters et al, 2010). Supplemental feeding has been associated with lower lead levels in condors (Kelly et al, 2014). Adherence to food subsidies was greatest early in the reintroduction program.…”

Section: Introductionmentioning

confidence: 99%

“…Adherence to food subsidies was greatest early in the reintroduction program. Reliance on provisions has decreased over time as condors have increased their flight range and become more experienced at finding nonproffered food sources (Hall et al, 2007), leading to greater risk of lead exposure (Kelly et al, 2014). In California, lead poisoning in condors has led to non-lead ammunition outreach programs and in 2008, regulations prohibiting the use of lead ammunition for big game and nongame hunting activities within the condor range (California Fish and Game Commission, 2009;Ridley-Tree Condor Preservation Act, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Two decades of cumulative impacts to survivorship of endangered California condors in California

Kelly¹,

Rideout

Grantham

et al. 2015

Biological Conservation

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We investigated threats to the California condor (Gymnogyps californianus), a flagship endangered species, using individual data on survival during a 20 year period of intensive recovery efforts. Over the two decades of reintroductions, condors in California had an estimated median survival time of 7.8 years suggesting that 50% of condors are expected to survive in the wild long enough to contribute to recruitment. In general, annual mortality rates exceeded levels necessary for a stable population; however, mortality declined, reaching levels needed for population stability, during the second decade of re-establishment. Intensive management practices, including utility pole aversion training and clinical interventions to prevent lead-related deaths likely contributed to the decrease in mortality rates. Utility line collision and/or electrocution was an important factor causing mortality over the two decades; though, this threat has largely been mitigated through management and targeted efforts in high-risk areas. In the past, wildfires were not considered a major threat to survival of freeflying condors. However, our analyses suggest that forest fires are significantly linked to the hazard of death, and increased wildfire activity in California highlights this population's vulnerability to catastrophic losses from forest fire. Lead poisoning, which was a major driver in the population's decline, was a leading cause of death accounting for the greatest adult mortality, and lead exposure remains the most significant threat. Recent lead ammunition reduction efforts in the condor range in California hold promise for improving the recovery potential for this population.

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Section: Data Sourcesmentioning

confidence: 99%

Section: Threats To Survivalmentioning

confidence: 99%

Section: Threats To Survivalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Two decades of cumulative impacts to survivorship of endangered California condors in California

Kelly¹,

Rideout

Grantham

et al. 2015

Biological Conservation

Self Cite

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One Toxicology, One Health, One Planet

et al. 2018

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Supplementary feeding and endangered avian scavengers: benefits, caveats, and controversies

Cortés‐Avizanda

Blanco

DeVault³

et al. 2016

Frontiers in Ecol & Environ

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141

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Large avian scavengers are among the most vulnerable vertebrates, and many of their populations have declined severely in recent decades. To help mitigate this marked reduction in abundance, supplementary feeding stations (SFS; colloquially termed “vulture restaurants”) have been created worldwide, often without consideration of the scientific evidence supporting the suitability of the practice. SFS have been effective and important tools for conservation and reintroduction of avian scavengers. However, negative consequences can result from large aggregations of individual birds, disrupting intraguild processes and promoting density‐dependent decreases in productivity. At the community level, SFS favor the congregation of predators (ie facultative scavengers), increasing predation risk on small‐ and medium‐sized vertebrates in the vicinity of the SFS. These feeding stations might also affect processes of natural selection and even render populations maladapted to their natural environments. We also examine future scenarios for avian scavengers in relation to ecosystem services, to changes in agro‐grazing economies and in land uses, and ultimately to rewilding landscapes where SFS play a controversial role.

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Spatiotemporal Patterns and Risk Factors for Lead Exposure in Endangered California Condors during 15 Years of Reintroduction

Abstract: Large-scale

Cited by 34 publications

References 15 publications

Two decades of cumulative impacts to survivorship of endangered California condors in California

Two decades of cumulative impacts to survivorship of endangered California condors in California

One Toxicology, One Health, One Planet

Supplementary feeding and endangered avian scavengers: benefits, caveats, and controversies

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