Stable isotopes and fatty acid signatures reveal age- and stage-dependent foraging niches in tufted puffins
Bibliographic record
Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 363:287-298 (2008) - DOI: https://doi.org/10.3354/meps07477 Stable isotopes and fatty acid signatures reveal age- and stage-dependent foraging niches in tufted puffins Cory T. Williams1, Sara J. Iverson2, C. Loren Buck3,* 1School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA 2Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4JI, Canada 3Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska 99508, USA *Corresponding author. Email: afclb1@uaa.alaska.edu ABSTRACT: Major breeding failures of seabird populations are sometimes attributed to reduced egg laying or abandonment of incubation due to nutritional stress, yet diets during these reproductive stages are often poorly characterized. We used stable isotopes and fatty acid (FA) signatures to infer age- (adult vs. nestling) and stage-dependent foraging niches of tufted puffins Fratercula cirrhata captured in Chiniak Bay, Kodiak Island, Alaska, USA, from 2003 to 2005. Whole blood δ15N values indicated a seasonal shift in trophic niche of adults: 15N enrichment was consistent with a 0.47 to 0.68 increase in trophic level of feeding from pre-lay to late chick-rearing. Although incomplete turnover of blood cells from the pre-lay period likely contributed to intermediate δ15N values of incubating puffins, this was insufficient to account for differences between incubating and chick-rearing adults. Differences in δ15N and δ13C between chick-rearing adults and nestlings were small and inconsistent between years. Discriminant function analysis (DFA) using the 14 most abundant FAs classified individuals by reproductive stage and age within each year with a high level of accuracy (linear DFA: 93 to 99%; quadratic DFA: 80 to 92%). When all years were combined, accuracy of cross-validated classification remained high (linear DFA: 90%; quadratic DFA: 76%). Based on stable isotopes and FA signatures, we conclude that foraging niches are stage-dependent in this species and suggest that chick-rearing adults do not typically feed at a lower trophic level than nestlings but likely consume a different array of prey species. KEY WORDS: Stable isotopes · Fatty acids · Adipose tissue · Foraging ecology · Fratercula cirrhata · Seabirds · Gulf of Alaska Full text in pdf format PreviousNextCite this article as: Williams CT, Iverson SJ, Buck CL (2008) Stable isotopes and fatty acid signatures reveal age- and stage-dependent foraging niches in tufted puffins. Mar Ecol Prog Ser 363:287-298. https://doi.org/10.3354/meps07477 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 363. Online publication date: July 15, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".