Manx shearwater vision: the science and the numbers

Puffinus puffinus · order Procellariiformes · Birds: all the numbers

The manx shearwater has four colour channels, including violet (402, 452, 503 and 566 nm).^[1] Its sharpest vision resolves 8.9 cycles per degree, against 63.75 for people in this dataset.^[5] Its eyes cover about 285° with 16° seen by both eyes.^[12]

See it on your photo Back to How does the manx shearwater see?

4colour receptor classesMeasured
8.9cycles per degree (sharpness)Measured
285°field of viewMeasured

The manx shearwater (Puffinus puffinus) is a bird in the order Procellariiformes. Its eyes belong to the vision type Panoramic grain-eater and wader: four cone types, low to moderate sharpness and an almost all-round field of view. 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 2026-10-02. Every value below carries its evidence level and sources; nothing is typed by hand.

What the manx shearwater sees: colour receptors

Manx shearwater: 402, 452, 503, 566 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

It has 4 colour receptor classes; people have 3.
Its sharpest vision resolves 8.9 cycles per degree: the finest stripe pattern it can tell apart from grey.
Its eyes cover about 285° around the head, with 16° seen by both eyes at once.
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 manx shearwater (Puffinus puffinus), catalogue-v1
Dial	Value	Evidence	Sources	People
Colour	Colour receptors 4 receptor classes: 402 nm (VS/SWS (violet)), 452 nm (SWS (blue)), 503 nm (MWS (green)), 566 nm (LWS (long)) measured in this species	Measured	^[1]	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][2][3][4]
Sharpness	Acuity 8.9 cycles per degree median of 1 anatomical-ganglion rows (method priority rule)	Measured	^[5]	Acuity: 63.75 cycles per degree Measured^[6][7]
Field of view	Binocular overlap 16° median of 1 rows (eyes-at-rest rows preferred)	Measured	^[8]	Binocular overlap: 122.5° Measured^[9][10] Total field of view: 200° Measured (not re-verified)^[11] Blind area behind the head: 160° Derived^[11] Eye placement: frontal Derived^[9][10]
	Total field of view 285° measured in this species (extension 2026-10, fov-verified.csv)	Measured	^[12]
	Blind area behind the head 75° 360 - total field	Derived	^[12]
	Eye placement lateral frontal if binocular overlap >= 60 deg, else lateral	Derived	^[8]
	Binocular overlap (published value) 14° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds	Measured	^[12]
	Binocular field, vertical extent 90° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds	Measured	^[12]
	Field of one eye 148° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds	Measured	^[12]
	Total field (published value) 285° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds	Measured	^[12]
	Binocular field, widest at any elevation 18°; maximum binocular overlap (widest frontal binocular sector at any elevation); maximum binocular overlap (compiled)	Measured	^[13]
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	^[14][15][16]	Number of foveas: 1 Measured^[17] Fovea type: fovea Measured^[17]
Sharp zones (foveas)	Fovea type single central fovea (displaced dorso-temporally from retinal centre)	Group default	^[14][15][16]
Night vision	Activity pattern diurnal mode of 4 rows (of 4 rows): cathemeral; diurnal; not_nocturnal	Measured (not re-verified)	^{[18][19][1][20]}	Activity pattern: diurnal Measured (not re-verified)^{[21][22][23][1][24][25][26][20]} Pupil shape: vertical Group default^[27][28] Reflective layer (tapetum): no Measured^[29] Rods vs cones: cone-dominated Derived^{[21][22][23][1][24][25][26][20]} Night sensitivity (optical, against people): S = 0.93 µm² sr, 1 times people (log10 ratio 0) Derived^[30]
Night vision	Rods vs cones cone-dominated nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated	Derived	^{[18][19][1][20]}
Motion (flicker fusion)	Flicker fusion frequency 88.5 Hz median of 17 relatives in class Aves: Bubo virginianus, Melopsittacus undulatus, Passer domesticus, Taeniopygia guttata, Columba livia, Calypte anna	Group default	^{[31][32][33][34][35]}	Flicker fusion frequency: 60 Hz Measured^[33][34]

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

Sources

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.