How does the least flycatcher see?
The least flycatcher (Empidonax minimus) is a bird in the order Passeriformes. Its eyes belong to the vision type UV songbird, parrot and hummingbird.
Measured in this species: sharpness, field of view and night vision. Measured core: measured values on at least 3 of the 6 dials. Every value below carries its evidence level and sources; nothing is typed by hand.
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What stands out
- It has 4 colour receptor classes, including ultraviolet; people have 3.
- Its sharpest vision resolves 8.9 cycles per degree: the finest stripe pattern it can tell apart from grey.
- Its eyes cover about 334.8° around the head, with 25.45° seen by both eyes at once.
- It stops seeing flicker at 100 Hz, against 60 Hz for people in this dataset, so fast motion looks about 1.7 times slower to it.[11][12]
- Activity pattern: diurnal.
The six dials
Evidence levels: how the tiers work. "Measured" means a value measured in this species; "Estimated" values come from a close relative or an eye-size formula.
| Dial | Value | Evidence | Sources |
|---|---|---|---|
| Colour | Colour receptors 4 receptor classes: 367.5 nm (UVS), 443 nm (SWS (blue)), 502.5 nm (MWS (green)), 570 nm (LWS (long)) receptor set of nearest measured relative Serinus canaria (same order Passeriformes) | Group default | [1][2] |
| Ultraviolet yes: at least one receptor peaks in the ultraviolet | Group default | ||
| Sharpness | Acuity 8.9 cycles per degree median of 1 anatomical-ganglion rows (method priority rule) | Measured | [3] |
| Field of view | Binocular overlap 25.45° median of 1 rows (eyes-at-rest rows preferred) | Measured | [4] |
| Total field of view 334.8° rule: total = 360 - blind area | Derived | [4] | |
| Sharp zones (foveas) | Number of foveas 1 median of 29 relatives in order Passeriformes: Cardinalis cardinalis, Passerina cyanea, Cyanocitta cristata, Junco hyemalis, Melospiza melodia, Melozone crissalis | Group default | [5][6] |
| Fovea type single central fovea (displaced dorso-temporally from retinal centre) | Group default | [5][6] | |
| Night vision | Activity pattern diurnal mode of 3 rows (of 3 rows): diurnal; not_nocturnal | Measured (not re-verified) | [7][8][9] |
| Rods vs cones cone-dominated nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated | Derived | [7][8][9] | |
| Motion (flicker fusion) | Flicker fusion frequency 100 Hz median of 7 relatives in order Passeriformes: Passer domesticus, Taeniopygia guttata, Molothrus ater, Sturnus vulgaris, Cyanistes caeruleus, Ficedula albicollis | Group default | [10][11][12][13] |
Other senses
- magnetoreception: NOT RENDERED (no agreed visual percept) (Group default)
Related animals
- European starling same vision type
- House sparrow same vision type
- American tree sparrow same vision type
- Brown-headed cowbird same vision type
- Chipping sparrow same vision type
- Dark-eyed junco same vision type
More birds: all birds with measured vision data.
Sources
- Longcore T. 2023. A compendium of photopigment peak sensitivities and visual spectral response curves of terrestrial wildlife to guide design of outdoor nighttime lighting. Basic Appl Ecol 73:40-50. doi:10.1016/j.baae.2023.09.002. doi.org/10.5281/zenodo.8432720
- VPOD in-vivo (MSP / single-cell) lambda max compendium, file scp_cleaned.csv, VPOD GitHub (Frazer et al. 2025 bioRxiv 10.1101/2025.08.22.671864). github.com/VisualPhysiologyDB/visual-physiology-opsin-db/tree/main/scripts_n_notebooks/vpod_ML_workflows/mine_n_match/data_sources/lmax/vpod
- Caves EM, Fernandez-Juricic E, Kelley LA (2024) Ecological and morphological correlates of visual acuity in birds. J Exp Biol 227(2): jeb246063. Supplementary Table S1.. doi.org/10.1242/jeb.246063
- Tyrrell LP, Moore BA, Loftis C, Fernandez-Juricic E 2017 (data 2017). The hawk-eyed songbird: retinal morphology, eye shape, and visual fields of an aerial insectivore. Am Nat 189(6). Dryad doi:10.5061/dryad.n7140.. doi.org/10.1086/691404
- Moore BA, Tyrrell LP, Pita D, Bininda-Emonds ORP, Fernandez-Juricic E 2017. Does retinal configuration make the head and eyes of foveate birds move? Sci Rep 7: 38406. Appendix 1.. doi.org/10.1038/srep38406
- Rodrigues T, Matter MM, Chiodini A, et al. 2026. Foveal vision in fast-flying birds hunting on the wing. bioRxiv 2026.06.05.730304. doi.org/10.64898/2026.06.05.730304
- Anderson SR, Wiens JJ. 2017. Out of the dark: 350 million years of conservatism and evolution in diel activity patterns in vertebrates. Evolution 71:1944-1959. Dryad doi:10.5061/dryad.fg700. doi.org/10.5061/dryad.fg700
- Wilman H, Belmaker J, Simpson J, de la Rosa C, Rivadeneira MM, Jetz W. 2014. EltonTraits 1.0: species-level foraging attributes of the world's birds and mammals. Ecology 95:2027. BirdFuncDat.txt. doi.org/10.6084/m9.figshare.3559887.v1
- Moura et al. 2024. A phylogeny-informed characterisation of global tetrapod traits addresses data gaps and biases. PLoS Biol 22:e3002658. TetrapodTraits v3.0.1.. doi.org/10.5281/zenodo.22536349
- Boström JE, Dimitrova M, Canton C, Håstad O, Qvarnström A, Ödeen A. 2016. Ultra-rapid vision in birds. PLoS ONE 11(3): e0151099. S1 Table. doi.org/10.1371/journal.pone.0151099
- Healy K, McNally L, Ruxton GD, Cooper N, Jackson AL. 2013. Metabolic rate and body size are linked with perception of temporal information. Animal Behaviour 86:685-696. Table 1. doi.org/10.1016/j.anbehav.2013.06.018
- Inger R, Bennie J, Davies TW, Gaston KJ. 2014. Potential biological and ecological effects of flickering artificial light. PLoS ONE 9(5): e98631. Table 3. doi.org/10.1371/journal.pone.0098631
- Lafitte A, Sordello R, Legrand M, Nicolas V, Obein G, Reyjol Y. 2022. A flashing light may not be that flashy: A systematic review on critical fusion frequencies. PLoS ONE 17(12): e0279718. S10 File (CFF database). doi.org/10.1371/journal.pone.0279718
Every value cites its sources (all sources). Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this?