Ecological and social factors affecting the local habitat distribution of western sandpipers wintering at Bah?Santa Mar? Northwest Mexico
Bibliographic record
Abstract
The process of habitat selection often requires individuals to choose among habitats that differ in foraging profitability and predation danger. The local habitat distribution of Western Sandpipers (Calidris maur~] was studied at Bahia Santa Maria, northwest Mexico, for three non-breeding seasons (1 999-2002). Western Sandpipers are highly sexually dimorphic, males being lighter and smaller-billed than females, and thus males may use visual foraging more often, be more susceptible to interference, and be less vulnerable to predation than females. Bahia Santa Maria supports over 350,000 Western Sandpipers in a diverse mosaic of habitats. Three habitats were categorized - brackish flats, mangroves, and cattail marshes- that differed with respect to food abundance and predation danger. Brackish flats were high-food and low-danger, while mangroves and cattail marshes were low-food and high-danger. Sandpiper and prey densities covaried positively among habitats, with brackish flats supporting the highest bird density. Males, and adults within each sex, were over-represented in brackish flats and mangroves. Sex ratios, and age ratios within each sex, were more evenly represented in cattail marshes. Compared with females, males were biased towards visual foraging and using drier substrates, changed their foraging behaviour more as flock size increased, were more likely to be territorial and aggressive, and allocated less time to anti-predator behaviour. Sex differences in foraging behaviour were consistent among habitats. Birds in brackish flats and mangroves were more biased towards visual foraging than those in cattail marshes. In brackish flats, birds changed their foraging behaviour more strongly with increasing flock size. Territoriality was observed in brackish flats and mangroves. Territory length appeared to be related to intruder pressure. Sandpipers apparently perceived cattail marshes as more dangerous than brackish flats and adjusted their anti-predator behaviour accordingly. Significant numbers of birds occurred in habitats with lower food availability and greater predation danger, suggesting a density-dependent devaluation of brackish flats. Overall, there is evidence that (0 females are more constrained by predation danger and males more constrained by interference, and (;I] that density-dependent competition is important in shaping local distributions of sandpipers during the non-breeding season.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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 source (direct Gemma or distilled Codex), 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".