Oblique color vision in an open-habitat bird: spectral sensitivity, photoreceptor distribution and behavioral implications
Bibliographic record
Abstract
Color vision is not uniform across the retina because of differences in photoreceptor density and distribution. Retinal areas with a high density of cone photoreceptors may overlap with those with a high density of ganglion cells, increasing hue discrimination. However, there are some exceptions to this cell distribution pattern, particularly in species with horizontal visual streaks (bands of high ganglion cell density across the retina) that live in open habitats. We studied the spectral sensitivity and distribution of cone photoreceptors involved in chromatic and achromatic vision in the Canada goose (Branta canadiensis), which possesses an oblique rather than horizontal visual streak at the ganglion cell layer. Using microspectrophotometry, we found that the Canada goose has a violet-sensitive visual system with four visual pigments with absorbance peaks at 409, 458, 509 and 580 nm. The density of most cones involved in chromatic and achromatic vision peaked along a band across the retina that matched the oblique orientation of the visual streak. With the information on visual sensitivity, we calculated chromatic and achromatic contrasts of different goose plumage regions. The regions with the highest visual saliency (cheek, crown, neck and upper tail coverts) were the ones involved in visual displays to maintain flock cohesion. The Canada goose oblique visual streak is the retinal center for chromatic and achromatic vision, allowing individuals to sample the sky and the ground simultaneously or the horizon depending on head position. Overall, our results show that the Canada goose visual system has features that make it rather different from that of other vertebrates living in open habitats.
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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 | 0.001 | 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".