Faunal Remains in California Condor Nest Caves

Collins, Paul W.; Snyder, Noel F. R.; Emslie, Steven D.

doi:10.1650/0010-5422(2000)102[0222:friccn]2.0.co;2

Cited by 13 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Across the years 1997-2010, the highest blood lead level recorded for condors in California was 6,100 ng/mL, with 12% of samples collected (i.e., n = 137 of 1154) exceeding 500 ng/mL. The higher risk of lead exposure in condors may be because of their extensive use of large mammal carcasses (18); condors have apparently always relied on large-bodied animals for food (19), including carcasses of both marine and large terrestrial mammals when available (20).…”

Section: Resultsmentioning

confidence: 99%

Lead poisoning and the deceptive recovery of the critically endangered California condor

Finkelstein

Doak

George

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

238

202

View full text Add to dashboard Cite

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.wildlife | ecotoxicology | hunting | demography | vulture

show abstract

Section: Resultsmentioning

confidence: 99%

Lead poisoning and the deceptive recovery of the critically endangered California condor

Finkelstein

Doak

George

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

238

202

View full text Add to dashboard Cite

show abstract

“…Indeed, extinct vultures were generally larger and possessed more extreme skull morphologies compared to extant species, indicating that intermediate sized scavengers were more likely to survive into the Holocene 8 . Extant vultures show high flexibility in foraging, as evidenced by their ability to exploit small carcasses 36,37,63,64 and a diversity of human-related carrion resources 65,66 . As human land-use intensifies, vultures have increasingly taken advantage of novel food sources.…”

Section: Discussionmentioning

confidence: 99%

Demography of avian scavengers after Pleistocene megafaunal extinction

Perrig

Fountain

Lambertucci

et al. 2019

Sci Rep

View full text Add to dashboard Cite

The late Quaternary megafauna extinctions reshaped species assemblages, yet we know little about how extant obligate scavengers responded to this abrupt ecological change. To explore whether obligate scavengers persisted by depending on contemporary community linkages or via foraging flexibility, we tested the importance of the trophic interaction between pumas ( Puma concolor ) and native camelids ( Vicugna vicugna and Lama guanicoe ) for the persistence of Andean condors ( Vultur gryphus ) in southern South America, and compared the demographic history of three vultures in different continents. We sequenced and compiled mtDNA to reconstruct past population dynamics. Our results suggest that Andean condors increased in population size >10 KYA, whereas vicuñas and pumas showed stable populations and guanacos a recent (<10 KYA) demographic expansion, suggesting independent trajectories between species. Further, vultures showed positive demographic trends: white-backed vultures ( Gyps africanus ) increased in population size, matching attenuated community changes in Africa, and California condors ( Gymnogyps californianus ) exhibited a steep demographic expansion ~20 KYA largely concurrent with North American megafaunal extinctions. Our results suggest that dietary plasticity of extant vulture lineages allowed them to thrive despite historical environmental changes. This dietary flexibility, however, is now detrimental as it enhances risk to toxicological compounds harbored by modern carrion resources.

show abstract

“…We also used published isotopic values of collagen from Holocene and modern pinnipeds from California (13) and from modern baleen and toothed whales from California (10). These animals were chosen for analysis, because condors are known to prefer to feed on large mammals, and cattle and deer make up a major component of condor diets today (4,21).…”

Section: Methodsmentioning

confidence: 99%

Pleistocene to recent dietary shifts in California condors

Chamberlain

Waldbauer²,

Fox-Dobbs³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

163

142

View full text Add to dashboard Cite

We used carbon and nitrogen isotopes to investigate changes in the diet of California condors from the Pleistocene to the recent. During the Pleistocene, condors from California fed on both terrestrial megafauna and marine mammals. Early accounts reported condors feeding on the carcasses of marine mammals, but by the late 1700s, condor diets had shifted predominantly to terrestrial animals, following the commercial harvesting of marine mammals and the development of cattle ranching on land. At present, dairy calves provided by humans significantly augment condor diet, constituting an artificial support of the current population. Reestablishing a marine mammal component in the condor diet may be an effective strategy for fostering viable condor populations independent of direct human subsidies.carbon isotopes ͉ nitrogen isotopes ͉ paleodiet D uring the Pleistocene, California condors (Gymnogyps californianus) ranged from the Pacific coast of North America across the southern U.S. to Florida and north to western New York (1, 2). Historical records show that by the 17th century, condors were restricted to the west coast of North America, from Baja California to British Columbia (3, 4). At present, small reintroduced populations live in California, Arizona, and Baja California. Paleontological evidence suggests that populations of these obligate scavengers were associated with the carcasses of large animals (1). After the late Pleistocene extinction of most large terrestrial mammals in North America (5), condors appear to have been restricted to the west coast, where stranded marine mammals offered the only remaining abundant source of large animal carcasses (1).There is little direct evidence that marine mammals were a significant component of condor diets, however, beyond scattered historical observations. In 1806, Lewis and Clark observed condors feeding on whales near the mouth of the Columbia River (6). Captain Clark wrote on February 16, 1806: ''This bird fly's very clumsily, nor do I know whether it ever seizes it's prey alive, but am induced to believe it does not. We have seen it feeding on the remains of the whale and other fish which have been thrown up by the waves on the sea coast. These I believe constitute their principal food, but I have no doubt but that they also feed on flesh.'' In 1855, Taylor found hundreds of condors feeding on sea lion carcasses on the California coast (7). He wrote: ''During the early part of the present month, large quantities of sea lions have been killed on the southern coast for the oil; the carcasses of these animals on the beach may be seen at times surrounded by hundreds of the Condors. A friend of ours informed us that he saw a few days ago, as many as three hundred of these creatures near such feeding ground, within a distance of a league.'' (7). In the 1860s, Cooper reported on condors feeding on seal and whale carcasses in California, although he never directly observed them doing so (8).To investigate changes in condor diets, we determined the stable carbon ( 12 C...

show abstract

Faunal Remains in California Condor Nest Caves

Cited by 13 publications

References 10 publications

Lead poisoning and the deceptive recovery of the critically endangered California condor

Lead poisoning and the deceptive recovery of the critically endangered California condor

Demography of avian scavengers after Pleistocene megafaunal extinction

Pleistocene to recent dietary shifts in California condors

Contact Info

Product

Resources

About