^(13)C and ^(15)N Enrichment Factors of Feathers of 11 Species of Adult Birds

Mizutani, Hiroshi; Fukuda, Michio; Kabaya, Yuko

doi:10.2307/1940684

Cited by 131 publications

(102 citation statements)

References 24 publications

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“…Mizutani et al (1990Mizutani et al ( , 1991 reported a ε feather-diet of 4‰ for stable carbon isotopes in free-ranging and captive cormorants and attributed the difference to the fractionation of 13 C as it is incorporated in the keratin of feathers. Mizutani et al (1992) extended this work to include other bird species and showed that ε feather-diet varied from 2.5 to 3.8‰, depending on species. Mizutani and Wada (1988), Mizutani et al (1990Mizutani et al ( , 1992 and Hobson and Clark (1992b) also observed significant differences in ε 13 C for regurgitant and feathers from free ranging and captive birds.…”

Section: Stable Isotopes and Tissue-diet Enrichment Factorsmentioning

confidence: 89%

“…Mizutani et al (1992) extended this work to include other bird species and showed that ε feather-diet varied from 2.5 to 3.8‰, depending on species. Mizutani and Wada (1988), Mizutani et al (1990Mizutani et al ( , 1992 and Hobson and Clark (1992b) also observed significant differences in ε 13 C for regurgitant and feathers from free ranging and captive birds. Variability was attributed to a variety of factors including the relationship between the timing of feather growth and seasonality in the composition of potential prey and/or the lipid content of prey items (Bender et al 1981;Sullivan and Krueger 1981;Hobson and Clark 1992a).…”

Section: Stable Isotopes and Tissue-diet Enrichment Factorsmentioning

confidence: 89%

“…The stable isotope signature of feather keratin has been used to document the feeding behavior and migratory patterns of various species of birds (Mizutani and Wada 1988;Mizutani et al 1990Mizutani et al , 1992Clark 1992a, 1992b;Chamberlain et al 1997;Hobson and Wassenaar 1997;Marra et al 1998). Feathers provide an optimal tissue for the study of endangered species because they represent a non-lethal source tissue that may be collected without invasive handling.…”

Section: Stable Isotopes As Tracers Of Life History Informationmentioning

confidence: 99%

“…This enrichment is expressed for every step up in trophic level throughout an ecosystem, resulting in high-trophiclevel consumers that are significantly enriched in 15 N compared with primary producers. Researchers have observed little intra-individual differences in the δ 15 N of various avian tissues, including feathers (Mizutani and Wada 1988;Mizutani et al 1991Mizutani et al , 1992Hobson and Clark 1992b). Thus, nitrogen isotope signatures in feather keratin may be used to distinguish birds that utilize differing food resources, provided that ecosystem resources are isotopically distinct and/or foraging strategies differ among colonies.…”

Section: Isotopic Analysesmentioning

confidence: 99%

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Foraging ecology of the endangered wood stork recorded in the stable isotope signature of feathers

et al. 2000

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Down feathers and regurgitant were collected from nestling wood storks (Mycteria americana) from two inland and two coastal breeding colonies in Georgia. The stable isotopic ratios of carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N) in these materials were analyzed to gain insights into the natal origins of juvenile storks and the foraging activities of adults. Down feathers differed in δ 13 C between inland and coastal colonies, having average isotopic values that reflected the sources of carbon fixed in biomass at the base of the food web. Feathers from the inland colonies differed between colonies in δ 15 N, while those from the coastal colonies did not. These patterns primarily reflected the foraging activities of parent storks, with individuals capturing differing percentages of prey of distinct trophic status at each colony. Collectively, the carbon and nitrogen isotopic signatures of feather keratin were used to distinguish nestlings from each colony, except for instances where storks from different colonies foraged in common wetlands. The stable isotopic composition of food items in regurgitant was used to reconstruct the trophic structure of the ecosystems in which wood storks foraged. Predicted foraging activities based on the isotopic composition of keratin were generally consistent with the percentage of prey types (freshwater vs. saltwater and lower trophic level vs. upper trophic level consumer) observed in regurgitant, except for the coastal colony at St. Simons Island, where the δ 13 C of feathers strongly suggested that freshwater prey were a significant component of the diet. This inconsistency was resolved by aerial tracking of adults during foraging excursions using a fixed-wing aircraft. Observed foraging activities supported interpretations based on the stable isotope content of feathers, suggesting that the latter provided a better record of overall foraging activity than regurgitant analysis alone. Observed foraging patterns were compared to the predictions of a statistical model that determined habitat utilization based on habitat availability using a geographic information system (GIS) database. Observed foraging activities and those predicted from feathers both suggested that some adult storks preferred to feed their young freshwater prey, even when saltwater resources were more accessible in the local environment. This conclusion supports the contention that wood stork populations are sensitive to changes in the distribution of freshwater habitats along the southeastern coastal plain of the United States.

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Section: Stable Isotopes and Tissue-diet Enrichment Factorsmentioning

confidence: 89%

Section: Stable Isotopes and Tissue-diet Enrichment Factorsmentioning

confidence: 89%

Section: Stable Isotopes As Tracers Of Life History Informationmentioning

confidence: 99%

Section: Isotopic Analysesmentioning

confidence: 99%

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Foraging ecology of the endangered wood stork recorded in the stable isotope signature of feathers

et al. 2000

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“…In general, consumer tissues are enriched in 15 N and 13 C relative to their diet by Ϸ3‰ and Ϸ1‰, respectively (26). However, controlled isotopic studies of diet and bird tissues show that these isotopic fractionations can vary significantly among tissue types and bird species (9,27,28). Although there are no controlled feeding studies of condors, recent work suggests that, as the protein content of diet rises, the diet-to-tissue fractionation increases for both carbon and nitrogen (28,29).…”

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.

164

142

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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...

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Stable carbon and nitrogen isotopic composition of diet and hair of Gidra-speaking Papuans

Yoshinaga

Minagawa

Suzuki

et al. 1996

Am. J. Phys. Anthropol.

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The carbon and nitrogen stable isotopic composition of the scalp hair and diet of Gidra-speaking people in four villages in Papua New Guinea is presented. The isotopic composition of hair was measured, while that of the diet was estimated from food consumption survey data and the measured isotopic composition and protein and carbohydrate contents of food items. The average isotopic ratios of the hair samples and of the diet varied among the four study villages, which were selected because of their diverse ecological settings. Comparison was made between hair and calculated dietary isotopic compositions. Two of the four diet-hair enrichment values obtained for 13C (+1.8 and 2.2%) were similar to those previously reported (1.4-2.0%), but the other two values (3.7 and 4.8%) were greater than in earlier reports. 15N enrichment was systematically greater (by 1.0%) than reported values (4.3%) except for one village, where a much greater enrichment (6.9%) was found. The factors potentially relevant to these deviations are discussed. Possible errors in estimating the dietary isotopic composition and minor modifications of dietary habits revealed by food consumption surveys could explain most of the discrepancies. However, the great enrichment of 15N found in one of the villages remains unexplained.

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^(13)C and ^(15)N Enrichment Factors of Feathers of 11 Species of Adult Birds

Cited by 131 publications

References 24 publications

Foraging ecology of the endangered wood stork recorded in the stable isotope signature of feathers

Foraging ecology of the endangered wood stork recorded in the stable isotope signature of feathers

Pleistocene to recent dietary shifts in California condors

Stable carbon and nitrogen isotopic composition of diet and hair of Gidra-speaking Papuans

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