Optimal descent angles for shallow-diving cormorants
Bibliographic record
Abstract
Air-breathing divers should attempt to maximize foraging efficiency under the constraint of limited oxygen availability. For diving water birds, high buoyancy (owing to the air in the plumage) and the associated change in buoyancy with diving depth impose further constraints on the adaptation to aquatic life. Diving birds are expected to descend as fast as possible to escape the higher buoyancy near the water surface, but in practice, shallow-diving cormorants (genus Phalacrocorax Brisson, 1760) are often observed descending the water column in relatively small angles with respect to the water surface. We derive a theoretical biomechanical model for the energetics of the descent phase of a dive of foot-propelled cormorants feeding on benthic prey at shallow depth. The model shows that visually guided benthic feeders benefit energetically from diving at small descent angles when optical conditions and bottom depth allow. The model also explains the high variation in descent angles observed in free-ranging birds, as well as the observed correlation between descent angle and bottom depth in cormorants.
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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 | 0.001 |
| 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".