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Common blackbird vision: the science and the numbers

Turdus merula · order Passeriformes · Birds: all the numbers

The common blackbird has four colour channels, including ultraviolet (373, 454, 504 and 557 nm).[1][2] Its sharpest vision resolves 22.5 cycles per degree, against 63.75 for people in this dataset.[6]

See it on your photoBack to How does the common blackbird see?
  • 4colour receptor classesMeasured
  • 22.5cycles per degree (sharpness)Measured

The common blackbird (Turdus merula) 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 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 the common blackbird sees: colour receptors

Common blackbird colour receptor peaks, 300 to 700 nmCommon blackbird: 4 receptor peaks at 373, 454, 504, 557 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Common blackbird: 373, 454, 504, 557 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 22.5 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • 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 common blackbird (Turdus merula), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
4 receptor classes: 373 nm (UVS), 454 nm (SWS (blue)), 504 nm (MWS (green)), 557 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
22.5 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
35°
median of 26 relatives in order Passeriformes: Baeolophus bicolor, Corvus albus, Corvus brachyrhynchos, Corvus corax, Corvus corone, Corvus frugilegus
Group default[9][10]Binocular overlap: 122.5° Measured[11][12]
Total field of view: 200° Measured (not re-verified)[13]
Blind area behind the head: 160° Derived[13]
Eye placement: frontal Derived[11][12]
Eye placement
lateral		Group default[9][10]
Sharp zones (foveas)Number of foveas
1
median of 1 relatives in genus Turdus: Turdus migratorius
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 8 rows (of 8 rows): cathemeral; diurnal; not_nocturnal
Measured (not re-verified)[16][17][18][19][20][2][21][22]Activity pattern: diurnal Measured (not re-verified)[16][23][24][2][25][26][27][22]
Pupil shape: vertical Group default[28][29]
Reflective layer (tapetum): no Measured[30]
Rods vs cones: cone-dominated Derived[16][23][24][2][25][26][27][22]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[16][17][18][19][20][2][21][22]
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[31][32][33][34]Flicker fusion frequency: 60 Hz Measured[32][33]

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. Tyrrell et al. 2017
  11. Heesy 2004
  12. Heffner et al. 1992
  13. Campbell & Green 1965
  14. Moore et al. 2017
  15. Kopania et al. 2025
  16. Anderson et al. 2017
  17. Angielczyk et al. 2014
  18. Light conditions and the evolution of…
  19. Choiniere et al. 2021
  20. Wilman et al. 2014
  21. Schmitz et al. 2011
  22. Moura et al. 2024
  23. Borges et al. 2018
  24. Wilman et al. 2014
  25. Maor et al. 2017
  26. Jones et al. 2009
  27. Schmitz et al. 2011
  28. Banks et al. 2015
  29. Cervino et al. 2021
  30. Guareschi et al. 2025
  31. Boström et al. 2016
  32. Healy et al. 2013
  33. Inger et al. 2014
  34. 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.