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Rook vision: the science and the numbers

Corvus frugilegus · order Passeriformes · Birds: all the numbers

Rooks have four colour channels, including ultraviolet (372.5, 443, 497 and 565 nm).[1][2] Their sharpest vision resolves 30 cycles per degree, against 63.75 for people in this dataset.[6] Both eyes see the same 13° in front of them.[9]

See it on your photoBack to How do rooks see?
  • 4colour receptor classesMeasured
  • 30cycles per degree (sharpness)Measured
  • 13°seen by both eyesMeasured

The rook (Corvus frugilegus) is a bird in the order Passeriformes. Its eyes belong to the vision type UV songbird, parrot and hummingbird: four cone types including a true ultraviolet cone, coloured oil droplets and fast motion vision. Measured in this species: colour, sharpness, field of view and night vision. 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 rooks see: colour receptors

Rook colour receptor peaks, 300 to 700 nmRook: 4 receptor peaks at 372.5, 443, 497, 565 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Rook: 372.5, 443, 497, 565 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 30 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 13° in front of it (binocular overlap), where depth is judged best.
  • 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. The last column gives the values for people from the same catalogue.

Vision values for the rook (Corvus frugilegus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
4 receptor classes: 372.5 nm (UVS), 443 nm (SWS (blue)), 497 nm (MWS (green)), 565 nm (LWS (long))
measured in this species
Measured[1][2]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][3][4][5]
Ultraviolet
yes: at least one receptor peaks in the ultraviolet		Measured
SharpnessAcuity
30 cycles per degree
median of 1 behavioural rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
13°
median of 1 rows (eyes-at-rest rows preferred)
Measured[9]Binocular overlap: 122.5° Measured[10][11]
Total field of view: 200° Measured (not re-verified)[12]
Blind area behind the head: 160° Derived[12]
Eye placement: frontal Derived[10][11]
Total field of view
335°
median total field (measured, or 360 - blind area) of relatives in genus Corvus: Corvus brachyrhynchos
Estimated[13]
Blind area behind the head
25°		Estimated[13]
Eye placement
lateral
frontal if binocular overlap >= 60 deg, else lateral
Derived[9]
Sharp zones (foveas)Number of foveas
1
median of 1 relatives in family Corvidae: Cyanocitta cristata
Estimated[14]Number of foveas: 1 Measured[15]
Fovea type: fovea Measured[15]
Fovea type
single central fovea (displaced dorso-temporally from retinal centre)		Estimated[14]
Night visionActivity pattern
diurnal
mode of 4 rows (of 4 rows): diurnal; not_nocturnal
Measured (not re-verified)[16][17][2][18]Activity pattern: diurnal Measured (not re-verified)[19][20][21][2][22][23][24][18]
Pupil shape: vertical Group default[25][26]
Reflective layer (tapetum): no Measured[27]
Rods vs cones: cone-dominated Derived[19][20][21][2][22][23][24][18]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[16][17][2][18]
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[28][29][30][31]Flicker fusion frequency: 60 Hz Measured[29][30]

Other senses

  • magnetoreception: NOT RENDERED (no agreed visual percept) (Group default)

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. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Caves et al. 2018
  7. Kirk et al. 2004
  8. Veilleux et al. 2014
  9. Tyrrell et al. 2017
  10. Heesy 2004
  11. Heffner et al. 1992
  12. Campbell & Green 1965
  13. Tyrrell et al. 2017
  14. Moore et al. 2017
  15. Kopania et al. 2025
  16. Light conditions and the evolution of…
  17. Wilman et al. 2014
  18. Moura et al. 2024
  19. Anderson et al. 2017
  20. Borges et al. 2018
  21. Wilman et al. 2014
  22. Maor et al. 2017
  23. Jones et al. 2009
  24. Schmitz et al. 2011
  25. Banks et al. 2015
  26. Cervino et al. 2021
  27. Guareschi et al. 2025
  28. Boström et al. 2016
  29. Healy et al. 2013
  30. Inger et al. 2014
  31. Lafitte et al. 2022

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.