Studying the diet of consumers using stable isotopes provides insight into the foraging ecology of individuals and species. To accurately reconstruct the integrated diet of animals using stable isotope values, we must quantify diet-tissue discrimination factors (DTDFs), or the way in which stable isotopes in prey are incorporated into the tissues of consumers. To quantify DTDFs, controlled experiments are needed, whereby consumers are fed a constant diet. However, relatively few controlled-diet studies have been conducted for seabirds. In this study, captive adult Atlantic puffins (Fratercula arctica) and common murres (Uria aalge) were fed a two-source diet of capelin (Mallotus villosus) and Atlantic silverside (Menidia menidia) to determine the DTDFs for the cellular component of blood and plasma for both δ15N and δ13C. The DTDFs for the cellular component (Δ15N: 2.80±0.28; Δ13C: 1.21±0.22) and plasma (Δ15N: 1.72±1.03; Δ13C: -0.18±0.56) of puffins were similar to those for the cellular component (Δ15N: 2.91±0.18; Δ13C: 1.09±0.23) and plasma (Δ15N: 2.18±0.77; Δ13C: -0.70±0.18) of murres. We reconstructed the diet of wild murres and puffins breeding on the northeastern coast of Newfoundland using previously published DTDFs and estimated DTDFs from our feeding experiment. Reconstructed dietary proportions supported a priori knowledge of diet, although outputs were sensitive to the DTDF used. Despite the similarity of our DTDFs for puffins and murres, along with the similarity of our DTDFs with those of other seabird species, our sensitivity analysis revealed considerable differences among resultant dietary contributions from mixing models, further highlighting the importance of using species- and tissue-specific DTDFs to enhance knowledge in the foraging ecology of seabirds using stable isotopes.

中文翻译：

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圈养和野生共同穆尔（Uria aalge）和大西洋海雀（Fratercula arctica）中的同位素歧视（δ15N，δ13C）。

使用稳定同位素研究消费者的饮食，可以深入了解个体和物种的觅食生态。为了使用稳定的同位素值准确地重建动物的综合饮食，我们必须量化饮食组织歧视因子（DTDF），或者将猎物中的稳定同位素掺入消费者组织的方式。为了定量DTDF，需要进行对照实验，从而为消费者提供恒定的饮食。但是，对海鸟进行的饮食控制研究相对较少。在这项研究中，给圈养的成年大西洋海雀（Fratercula arctica）和常见的褐变（Uria aalge）喂食了两种来源的毛鳞鱼（Mallotus villosus）和大西洋银糖苷（Menidia menidia），以确定血液和血液中细胞成分的DTDF。 δ15N和δ13C的等离子体。海雀的细胞成分（Δ15N：2.80±0.28;Δ13C：1.21±0.22）和血浆（Δ15N：1.72±1.03;Δ13C：-0.18±0.56）的DTDF与细胞成分（Δ15N：2.91± 0.18;Δ13C：1.09±0.23）和血浆（Δ15N：2.18±0.77;Δ13C：-0.70±0.18）。我们使用先前发表的DTDF和根据我们的喂养实验估算出的DTDF，重建了纽芬兰东北海岸野生海和海雀繁殖的饮食。重构的饮食比例支持先验饮食知识，尽管产出对使用的DTDF敏感。尽管我们对海雀和海藻的DTDF相似，并且与其他海鸟物种的DTDF相似，但我们的敏感性分析显示，混合模型在日粮中的贡献很大，