Is there more than one way to cross the Caribbean Sea? Migratory strategies of Nearctic-Neotropical landbirds departing from northern Colombia
Bibliographic record
Abstract
For migratory landbird species, large expanses of open water or inhospitable areas provide unique challenges during migration. Research on the strategies that species use to navigate barriers can yield insights into the factors shaping the evolution of migration and facilitate the identification of critical staging areas prior to barrier crossing. One such barrier, the Caribbean Sea, has received little study but must be negotiated by ≈50 migratory landbirds as they fly from South America to North America in spring. Recent discoveries from the Gray-cheeked Thrush (Catharus minimus), which undertakes non-stop flights >3000 km across the Caribbean Sea, raises the possibility that the breadth of potential strategies has been unappreciated thus far. We calculated fuel load and potential flight range in 9985 individuals of 16 species captured over 10 years at two stopover sites in northern Colombia to 1) evaluate the likely migratory strategy of these species as they depart northern Colombia in spring, and 2) evaluate the influence of family, diet, morphology and migratory distance on potential flight range. We found considerable variation in flight ranges and therefore strategies for crossing the Caribbean Sea/Gulf of Mexico barrier complex. In addition to Gray-cheeked Thrush, non-stop flights >2500 km were possible in Yellow-billed Cuckoo (Coccyzus americanus), Yellow Warbler (Setophaga petechia) and Northern Waterthrush (Parkesia noveboracensis). The remaining species were either capable of over-water flights to the Yucatan Peninsula/Cuba (>1800 km) or shorter flights to middle Central America (>1000 km) and likely required one or more stopovers to reach North America. Predicted flight ranges were influenced by morphology but not by distance, diet or taxonomic group, providing a novel insight into the evolution of migratory strategies. Our study confirms the vital role northern Colombia performs in providing energy for migratory birds and highlights the Caribbean as a key migratory barrier for many species.
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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) | 0.001 | 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".