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Brown falcon vision: the science and the numbers

Falco berigora · order Falconiformes · Birds: all the numbers

Its sharpest vision resolves 73 cycles per degree, against 63.75 for people in this dataset.[6] Its activity pattern is diurnal.[17][18][19]

See it on your photoBack to How does the brown falcon see?
  • 73cycles per degree (sharpness)Measured

The brown falcon (Falco berigora) is a bird in the order Falconiformes. Its eyes belong to the vision type Raptor telephoto: four cone types, two foveas and very high sharpness. Measured in this species: sharpness, foveas 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 brown falcon sees: colour receptors

Brown falcon colour receptor peaks, 300 to 700 nmBrown falcon: 4 receptor peaks at 417.5, 452, 501, 570 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Brown falcon: 417.5, 452, 501, 570 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • Its sharpest vision resolves 73 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 brown falcon (Falco berigora), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
4 receptor classes: 417.5 nm (VS/SWS (violet)), 452 nm (SWS (blue)), 501 nm (MWS (green)), 570 nm (LWS (long))
receptor set of nearest measured relative Anas platyrhynchos (same class Aves)
Group default[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]
SharpnessAcuity
73 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
37°
median of 3 relatives in genus Falco: Falco sparverius, Falco biarmicus, Falco cherrug
Estimated[9][10][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
292°
median total field (measured, or 360 - blind area) of relatives in genus Falco: Falco sparverius
Estimated[10]
Blind area behind the head
68°		Estimated[10]
Eye placement
lateral		Estimated[9][10][11]
Sharp zones (foveas)Number of foveas
2
species-v1.csv text: 2 (central deep + temporal shallow)
Measured (not re-verified)[15]Number of foveas: 1 Measured[16]
Fovea type: fovea Measured[16]
Fovea type
central fovea, temporal		Measured (not re-verified)[15]
Night visionActivity pattern
diurnal
mode of 3 rows (of 3 rows): diurnal; not_nocturnal
Measured (not re-verified)[17][18][19]Activity pattern: diurnal Measured (not re-verified)[20][21][22][2][23][24][25][19]
Pupil shape: vertical Group default[26][27]
Reflective layer (tapetum): no Measured[28]
Rods vs cones: cone-dominated Derived[20][21][22][2][23][24][25][19]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[17][18][19]
Motion (flicker fusion)Flicker fusion frequency
113.25 Hz
median of 2 relatives in genus Falco: Falco peregrinus, Falco cherrug
Estimated[29][30]Flicker fusion frequency: 60 Hz Measured[31][32]

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. Potier et al. 2023
  10. Tyrrell et al. 2017
  11. Tyrrell et al. 2017
  12. Heesy 2004
  13. Heffner et al. 1992
  14. Campbell & Green 1965
  15. Reymond 1987
  16. Kopania et al. 2025
  17. Light conditions and the evolution of…
  18. Wilman et al. 2014
  19. Moura et al. 2024
  20. Anderson et al. 2017
  21. Borges et al. 2018
  22. Wilman et al. 2014
  23. Maor et al. 2017
  24. Jones et al. 2009
  25. Schmitz et al. 2011
  26. Banks et al. 2015
  27. Cervino et al. 2021
  28. Guareschi et al. 2025
  29. Haarlem et al. 2026
  30. Lafitte et al. 2022
  31. Healy et al. 2013
  32. 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.