Stick supply to nests by cliff-nesting raptors as an evolutionary load of past tree-nesting
Bibliographic record
Abstract
The supply of sticks to cliff nests by many European raptors has been explained only as a functional means of decreasing ectoparasite loads in nests and for signalling nest occupancy. We provide here a historical explanation of this behaviour as we consider it represents an evolutionary load of formerly tree-nesting species. Basically, from this perspective, facultative tree/cliff-nesting species reproduce the nests they used to build originally on top of trees, but on cliffs. Facultative species (likely evolved in forested areas) that supply their cliff nests with sticks include Pandion haliaetus, Haliaetus albicilla, Milvus migrans, Circaetus gallicus, Buteo buteo, Aquila fasciata, A. pennata, A. chrysaetos, A. heliaca, Gypaetus barbatus Gyps fulvus and Neophron percnopterus. On the contrary, the only Falco species that solely nests in cliffs (F. eleonorae)) and does not supply its nests with sticks and should be considered a true cliff-nester, likely evolved in non-forested areas. All other Falco species that do not supply their cliff nests with sticks but can make use of tree nests made by other non-raptorial species, should also be considered as true cliff-nesters, likely evolved in more forested areas or times. Milvus milvus, Elanus caeruleus, Accipiter nisus, A. gentilis, Pernis apivorus, Aquila adalberti, A. clanga, A. pomarina and Aegypius monachus are true tree nesters, likely evolved in forested areas, which did not evolve the plasticity to nest directly on cliffs.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".