Lead Intoxication Kinetics in Condors from California

Fry, Michael

doi:10.4080/ilsa.2009.0301

Cited by 19 publications

(19 citation statements)

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“…The results were consistent with ingestion of lead being followed, in the absence of further ingestion, by a progressive exponential diminution in its concentration in the blood, with a half-life of 17 days. This pattern is broadly similar to that found in a previous study of captive condors with initially high levels of lead in the blood [7] .…”

Section: Discussionsupporting

confidence: 89%

Effectiveness of Action to Reduce Exposure of Free-Ranging California Condors in Arizona and Utah to Lead from Spent Ammunition

et al. 2008

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California condors (Gymnogyps californianus) released into the wild in Arizona ranged widely in Arizona and Utah. Previous studies have shown that the blood lead concentrations of many of the birds rise because of ingestion of spent lead ammunition. Condors were routinely recaptured and treated to reduce their lead levels as necessary but, even so, several died from lead poisoning. We used tracking data from VHF and satellite tags, together with the results of routine testing of blood lead concentrations, to estimate daily changes in blood lead level in relation to the location of each bird. The mean daily increment in blood lead concentration depended upon both the location of the bird and the time of year. Birds that spent time during the deer hunting season in two areas in which deer were shot with lead ammunition (Kaibab Plateau (Arizona) and Zion (Utah)) were especially likely to have high blood lead levels. The influence upon blood lead level of presence in a particular area declined with time elapsed since the bird was last there. We estimated the daily blood lead level for each bird and its influence upon daily mortality rate from lead poisoning. Condors with high blood lead over a protracted period were much more likely to die than birds with low blood lead or short-term elevation. We simulated the effect of ending the existing lead exposure reduction measures at Kaibab Plateau, which encourage the voluntary use of non-lead ammunition and removal of gut piles of deer and elk killed using lead ammunition. The estimated mortality rate due to lead in the absence of this program was sufficiently high that the condor population would be expected to decline rapidly. The extension of the existing lead reduction program to cover Zion (Utah), as well as the Kaibab plateau, would be expected to reduce mortality caused by lead substantially and allow the condor population to increase.

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Section: Discussionsupporting

confidence: 89%

Effectiveness of Action to Reduce Exposure of Free-Ranging California Condors in Arizona and Utah to Lead from Spent Ammunition

et al. 2008

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“…But some carcasses could still have been available from supplemental hunting, shot livestock or coyotes ( Canis latrans ; Stauber et al 2010), or after snow melted off previously covered carcasses (Neumann 2009). Additionally, BLL should have decreased because the half‐life of lead is often considered to be 14 days after exposure based on work with California condors (Fry et al 2009). Even though young birds tend to outcompete adults at carcasses (Gjershaug et al 2019), BLL remained high across the season for adults (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Some golden eagles had BLL high enough for the bird to be considered lethally exposed (>120 μg/dL). The mean half‐life of lead in golden eagles is assumed to be about 14 days, based on work with California condors ( Gymnogyps californianus ; Fry et al 2009). Some ingested lead can be stored in tissues and later remobilize into the blood (Rabinowitz et al 1976), so repeated exposures may maintain or further elevate BLL in golden eagles.…”

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Widespread Lead Exposure in Golden Eagles Captured in Montana

Domenech¹,

Shreading²,

Ramsey³

et al. 2020

J Wildl Manag

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Lead poisoning threatens many species of raptors, including golden eagles (Aquila chrysaetos). Much of this lead likely comes from bullet fragments that remain in the carcasses of animals killed by hunters. The likelihood of lead exposure may peak during fall hunting seasons and early winter until carcasses from hunting become scarce. From 2011 to 2018 in western Montana, USA, we captured 91 golden eagles in winter, tested their blood lead levels (BLL), and outfitted a subset of birds (n = 29) with global positioning system [GPS] transmitters. Nearly all golden eagles (94.5%) had elevated BLL (≥10 μg/dL), and 8 of them had BLL above clinical exposure (>60 μg/dL), where they may lose coordination and experience a host of other neurological and physiological disorders. Golden eagles caught late in winter tended to have lower BLL than those caught earlier. At least 69% of the golden eagles equipped with GPS transmitters migrated northward, spending the summer throughout Alaska, USA, and northwestern Canada. Blood lead levels did not differ between migratory and nonmigratory golden eagles. Overall, elevated BLL are widespread among golden eagles throughout winter in western Montana. Promoting nonlead hunting ammunition in areas with high densities of golden eagles will reduce the birds' lead exposure. © 2020 The Wildlife Society.

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“…The length and timing of these periods were 4 fixed time intervals of 2, 7, 14, and 30 days before blood collection and 2 1‐week intervals, from day 15–21 and from day 31–37 prior to blood collection. We used these specific lengths and timings based on the half‐life of lead in condor blood samples (14 days; Fry et al ) and on deviations from that half‐life that we deemed might reasonably capture the uncertainty caused by our lack of knowledge of the time of lead exposure.…”

Section: Methodsmentioning

confidence: 99%

Lack of observed movement response to lead exposure of California condors

et al. 2017

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Lead poisoning is an important conservation concern for wildlife, and scavenging birds are especially at risk from consumption of carcasses of animals killed with lead ammunition. Because current methods to identify lead exposure require animal capture and blood collection, management would benefit from the development of a less costly and noninvasive behavioral test for illness in wild animals. We attempted to design such a test to identify lead exposure in California condors (Gymnogyps californianus) that we tracked with global positioning system (GPS) telemetry in southern California, USA, 2013-2016. We measured blood-lead concentrations in tracked birds and expected that flight behavior would be influenced by lead exposure; thus, we measured the effect of blood-lead concentrations on 2 different types of movement rates and on the proportion of time condors spent in flight. We found no effect of lead exposure on any of these 3 behavioral metrics. Our work suggests that the measurements we took of flight behaviors were not a useful tool in predicting lead exposure in the mildly to moderately exposed birds we studied. Wild birds are effective at hiding illness, especially condors who have a strong social hierarchy in which showing weakness is a disadvantage. However, focusing on behaviors other than flight, expanding the sample studied to include birds with a wider range of lead concentration values, or analyzing tissues such as feathers (rather than, or in addition to, blood) may be more useful for identification of lead exposure and other diseases that may limit wildlife populations. Ó 2017 This article is a U.S. Government work and is in the public domain in the USA.

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Lead Intoxication Kinetics in Condors from California

Cited by 19 publications

References 0 publications

Effectiveness of Action to Reduce Exposure of Free-Ranging California Condors in Arizona and Utah to Lead from Spent Ammunition

Effectiveness of Action to Reduce Exposure of Free-Ranging California Condors in Arizona and Utah to Lead from Spent Ammunition

Widespread Lead Exposure in Golden Eagles Captured in Montana

Lack of observed movement response to lead exposure of California condors

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