Small scale, elevation- and environmental-related differences in life history strategies in a temperate resident songbird
Bibliographic record
Abstract
Environmental drivers of within-population reproductive patterns are often hypothesized to lead to reproductive strategies tuned to local conditions. Organisms adjust energy allocation between survival and reproduction based on experience, age, lifespan and resource availability. Variation in these energetic investments can be described as different demographic tactics which are expected to optimize the fitness of local populations. These ideas are largely supported by both empirical and model-based studies but research identifying specific strategies and their corresponding environmental drivers within wild populations remains rare. Using 12 years of data, we investigated reproductive investment strategies in a relatively short-lived resident songbird, the mountain chickadee ( Poecile gambeli ), at two elevations that differ in environmental harshness in the North American Sierra Nevada mountains. Challenging winter environments at high elevations impose strong selection pressure on survival-related traits (e.g. specialized spatial cognition associated with food caching) and significantly shorten the length of the reproductive window. Here, we show that chickadees at a higher elevation lay smaller clutches ( ca 0.41 fewer eggs) and produce fewer ( ca 0.25 fewer nestlings) but larger offspring ( ca 0.4 g heavier) compared to lower elevation residents. Due to the harsher and less predictable environmental conditions at higher elevations, this investment strategy in this resident species likely leads to the production of offspring with greater chances of survival. Overall, our results show that within-species differences in life history strategies may evolve over a small spatial scale along strong environmental gradients.
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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 | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".