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Black phoebe vision: the science and the numbers

Sayornis nigricans · order Passeriformes · Birds: all the numbers

Its sharpest vision resolves 8.88 cycles per degree, against 63.75 for people in this dataset.[6] Both eyes see the same 32° in front of it.[9]

See it on your photoBack to How does the black phoebe see?
  • 8.88cycles per degree (sharpness)Measured
  • 32°seen by both eyesMeasured

The black phoebe (Sayornis nigricans) 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: 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 the black phoebe sees: colour receptors

Black phoebe colour receptor peaks, 300 to 700 nmBlack phoebe: 4 receptor peaks at 367.5, 443, 502.5, 570 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Black phoebe: 367.5, 443, 502.5, 570 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • Its sharpest vision resolves 8.88 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 32° 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 black phoebe (Sayornis nigricans), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour 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]Colour receptors: 3 receptor classes: 421.5 nm (VS/SWS (violet)), 532 nm (MWS (green)), 558.4 nm (LWS (long)) Measured (not re-verified)[1][3][4][5]
Ultraviolet
yes: at least one receptor peaks in the ultraviolet		Group default
SharpnessAcuity
8.88 cycles per degree
median of 1 anatomical-ganglion rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
32°
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
333.5°
median total field (measured, or 360 - blind area) of relatives in family Tyrannidae: Empidonax virescens, Empidonax minimus
Estimated[13]
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[14][15]Number of foveas: 1 Measured[16]
Fovea type: fovea Measured[16]
Fovea type
single central fovea (displaced dorso-temporally from retinal centre)		Group default[14][15]
Night visionActivity pattern
diurnal
mode of 2 rows (of 2 rows): diurnal; not_nocturnal
Measured (not re-verified)[17][18]Activity pattern: diurnal Measured (not re-verified)[19][20][21][1][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][1][22][23][24][18]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[17][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. Longcore 2023
  2. VPOD in-vivo (MSP / single-cell) lambda… 2025
  3. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Caves et al. 2024
  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. Rodrigues et al. 2026
  16. Kopania et al. 2025
  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.