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Great horned owl vision: the science and the numbers

Bubo virginianus · order Strigiformes · Birds: all the numbers

Great horned owls have four colour channels, including ultraviolet (373, 454, 504 and 555 nm).[1][2][3] Their sharpest vision resolves 7.125 cycles per degree, against 63.75 for people in this dataset.[7][8] Both eyes see the same 41° in front of them.[11] Great horned owls stop seeing flicker at 40 Hz, against 60 Hz for people.[34]

See it on your photoBack to How do great horned owls see?
  • 4colour receptor classesMeasured
  • 7.125cycles per degree (sharpness)Measured*
  • 41°seen by both eyesMeasured
  • 40hertz flicker fusion (motion)Measured

The great horned owl (Bubo virginianus) is a bird in the order Strigiformes. Its eyes belong to the vision type Owl and night bird: rod-dominated eyes built for dim light, with low sharpness. Measured in this species: colour, sharpness, field of view, night vision and motion (flicker fusion). Measured core: measured values on at least 3 of the 6 dials.

This is a simulation built from published eye measurements, not what the animal experiences.

Method: How we know what animals see (the See Like Animals vision engine) · Sources · Last updated . Every value below carries its evidence level and sources; nothing is typed by hand.

What great horned owls see: colour receptors

Great horned owl colour receptor peaks, 300 to 700 nmGreat horned owl: 4 receptor peaks at 373, 454, 504, 555 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Great horned owl: 373, 454, 504, 555 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • It has 4 colour receptor classes, including ultraviolet; people have 3.
  • Its sharpest vision resolves 7.125 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 41° in front of it (binocular overlap), where depth is judged best.
  • It stops seeing flicker at 40 Hz, against 60 Hz for people in this dataset, so fast motion looks choppier to it.[35][36]
  • Activity pattern: nocturnal.

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. The last column gives the values for people from the same catalogue.

Vision values for the great horned owl (Bubo virginianus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
4 receptor classes: 373 nm (UVS), 454 nm (SWS (blue)), 504 nm (MWS (green)), 555 nm (LWS (long))
measured in this species
Measured[1][2][3]Colour receptors: 3 receptor classes: 421.5 nm (VS/SWS (violet)), 532 nm (MWS (green)), 558.4 nm (LWS (long)) Measured (not re-verified)[2][4][5][6]
Ultraviolet
yes: at least one receptor peaks in the ultraviolet		Measured
SharpnessAcuity
7.125 cycles per degree
median of 2 behavioural rows (method priority rule)
Measured (not re-verified)[7][8]Acuity: 63.75 cycles per degree Measured[9][10]
Field of viewBinocular overlap
41°
median of 1 rows (eyes-at-rest rows preferred)
Measured[11]Binocular overlap: 122.5° Measured[12][13]
Total field of view: 200° Measured (not re-verified)[14]
Blind area behind the head: 160° Derived[14]
Eye placement: frontal Derived[12][13]
Total field of view
201°
median species-v1 total field of family Strigidae: Strix aluco
Estimated[15]
Blind area behind the head
159°		Estimated[15]
Eye placement
lateral
frontal if binocular overlap >= 60 deg, else lateral
Derived[11]
Sharp zones (foveas)Number of foveas
1
median of 48 relatives in class Aves: Branta canadensis, Cardinalis cardinalis, Passerina cyanea, Zenaida macroura, Cyanocitta cristata, Junco hyemalis
Group default[16][17][18]Number of foveas: 1 Measured[19]
Fovea type: fovea Measured[19]
Fovea type
single central fovea (displaced dorso-temporally from retinal centre)		Group default[16][17][18]
Night visionActivity pattern
nocturnal
mode of 5 rows (of 5 rows): diurnal; nocturnal
Measured (not re-verified)[20][21][22][2][23]Activity pattern: diurnal Measured (not re-verified)[24][25][26][2][27][28][29][23]
Pupil shape: vertical Group default[30][31]
Reflective layer (tapetum): no Measured[32]
Rods vs cones: cone-dominated Derived[24][25][26][2][27][28][29][23]
Reflective layer (tapetum)
no		Measured (not re-verified)[33]
Rods vs cones
rod-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[20][21][22][2][23]
Motion (flicker fusion)Flicker fusion frequency
40 Hz
median of 1 bright-light rows (behavioural/whole-eye ERG rows; all rows: [40.0]); cff_hz: dim-light rows (bright-light rows used) set aside (labelled alternative: 45)
Measured[34]Flicker fusion frequency: 60 Hz Measured[35][36]

All birds side by side: Birds: every measurement. Method: how we know what animals see.

Sources

  1. Lind et al. 2014
  2. Longcore 2023
  3. VPOD in-vivo (MSP / single-cell) lambda… 2025
  4. Kirwan
  5. Müller et al. 2009
  6. Thermal Activation and Photoactivation of Visual… 2004
  7. Caves et al. 2018
  8. Potier et al. 2020
  9. Kirk et al. 2004
  10. Veilleux et al. 2014
  11. Potier et al. 2023
  12. Heesy 2004
  13. Heffner et al. 1992
  14. Campbell & Green 1965
  15. Martin 1984
  16. Moore et al. 2017
  17. Potier et al. 2017
  18. Rodrigues et al. 2026
  19. Kopania et al. 2025
  20. Light conditions and the evolution of…
  21. Choiniere et al. 2021
  22. Wilman et al. 2014
  23. Moura et al. 2024
  24. Anderson et al. 2017
  25. Borges et al. 2018
  26. Wilman et al. 2014
  27. Maor et al. 2017
  28. Jones et al. 2009
  29. Schmitz et al. 2011
  30. Banks et al. 2015
  31. Cervino et al. 2021
  32. Guareschi et al. 2025
  33. Healy et al. 2013
  34. Lafitte et al. 2022
  35. Healy et al. 2013
  36. Inger et al. 2014

Every value cites its sources (all sources). Values were extracted from these works and converted (units, medians, derived values); changes are ours, and the listed sources do not endorse this site. Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this? Method: how we know.