How good is chicken eyesight vs. raptors?

[amiachicknorwat]

centrarchid wrote in "what mite I do, naturally?" thread:

"The birds are also likely to want a good view while [dirt] bathing".

For me this brings up the question, how good is a chickens eyesight? When I was setting up the fishing line overhead of the run, criss-crossing it from fence post to post, I figured the relatively eagle-eyed raptors (even if they're not eagles) will see the filament. I added pieces of flagging tape to assure the chickens, not expecting their eyesight to be as keen. Tho I generally considered all birds to have good eyesight. I obviously wasn't thinking about it much then. Now I see the big diff. Not only are raptors dependent on keen and far sight, but they're generally up in the air. Observing the chicken's behaviour time and again they show signs of poor distance vision. It's the same for humans, really. Those of us regularly engaged in close-in work and recreation activity wear and need glasses compared with those working in fields and commonly looking/exercising/attuning their eyes to long views. Can anyone here corroborate or refute (agree or diss) this?

 

[nchls school]

centrarchid wrote in "what mite I do, naturally?" thread:

"The birds are also likely to want a good view while [dirt] bathing".

For me this brings up the question, how good is a chickens eyesight?  When I was setting up the fishing line overhead of the run, criss-crossing it from fence post to post, I figured the relatively eagle-eyed raptors (even if they're not eagles) will see the filament. I added pieces of flagging tape to assure the chickens, not expecting their eyesight to be as keen. Tho I generally considered all birds to have good eyesight. I obviously wasn't thinking about it much then. Now I see the big diff. Not only are raptors dependent on keen and far sight, but they're generally up in the air. Observing the chicken's behaviour time and again they show signs of poor distance vision. It's the same for humans, really. Those of us regularly engaged in close-in work and recreation activity wear and need glasses compared with those working in fields and commonly looking/exercising/attuning their eyes to long views. Can anyone here corroborate or refute (agree or diss) this?

Mother Nature has a way of eliminating adaptations that are unnecessary. Raptors need keen eyesight and a good sense of smell just to stay alive and even with these adaptations most young raptors never see their first birthday. It's a difficult job to fly through the air trying to spot a mouse, rabbit, our chickens; for many the job is too hard and they die.

Why would chickens need good eyesight or that strong sense of smell? They don't. God and nature does not waste abilities on creatures who have no need for them.

This I worded badly. In my mind I was comparing chickens and raptors. Yes. Chicken vision is better than humans; certainly better than mine. It blows my mind every time I see a chicken jump into the air and snatch a bug out of the air.

But as good as their vision may be it does not compare to the raptors.

Off the net.

Diurnal birds of prey[edit]

"Hawk-eyed" is a byword for visual acuity
The visual ability of birds of prey is legendary, and the keenness of their eyesight is due to a variety of factors. Raptors have large eyes for their size, 1.4 times greater than the average for birds of the same weight,[9] and the eye is tube-shaped to produce a larger retinal image. The retina has a large number of receptors per square millimeter, which determines the degree of visual acuity. The more receptors an animal has, the higher its ability to distinguish individual objects at a distance, especially when, as in raptors, each receptor is typically attached to a single ganglion.[1] Many raptors have foveas with far more rods and cones than the human fovea (65,000/mm2 in American kestrel, 38,000 in humans) and this provides these birds with spectacular long distance vision.[citation needed] The fovea itself can also be lens-shaped, increasing the effective density of receptors further.[citation needed] This combination of factors gives Buteo buzzards distance vision 6 to 8 times better than humans.[citation needed]


Each retina of the black-chested buzzard-eagle has two foveae[45]
The forward-facing eyes of a bird of prey give binocular vision, which is assisted by a double fovea.[2] The raptor's adaptations for optimum visual resolution (an American kestrel can see a 2–mm insect from the top of an 18–m tree) has a disadvantage in that its vision is poor in low light level, and it must roost at night.[1] Raptors may have to pursue mobile prey in the lower part of their visual field, and therefore do not have the lower field myopia adaptation demonstrated by many other birds.[1] Scavenging birds like vultures do not need such sharp vision, so a condor has only a single fovea with about 35,000 receptors mm2. Vultures, however have high physiological activity of many important enzymes to suit their distant clarity of vision [46][citation needed]

Raptors lack coloured oil droplets in the cones, and probably have similar colour perception to humans, and lack the ability to detect polarised light. The generally brown, grey and white plumage of this group, and the absence of colour displays in courtship suggests that colour is relatively unimportant to these birds.[2]

In most raptors a prominent eye ridge and its feathers extends above and in front of the eye. This "eyebrow" gives birds of prey their distinctive stare. The ridge physically protects the eye from wind, dust, and debris and shields it from excessive glare. The Osprey lacks this ridge, although the arrangement of the feathers above its eyes serves a similar function; it also possesses dark feathers in front of the eye which probably serve to reduce the glare from the water surface when the bird is hunting for its staple diet of fish.[5]

 

[Cacique500]

Two quick articles for reference...chickens have very good eyesight (better than humans in several areas - specifically color and motion):

http://www.fresheggsdaily.com/2013/10/do-you-see-what-i-see-12-fascinating.html

http://www.livescience.com/8099-chickens-color-humans.html

They have to have excellent vision or they'd be taken pretty quickly by the raptors. I know I've watched mine and they've spotted hawks flying waaaaay up there, to where I had to search to find them.

I also read (but can't find now) an article that said one eye is generally used for watching the sky and the other is close focused for searching the ground.

 

[amiachicknorwat]

Hi, In the do you see what I see from the fresheggsdaily site one of the 12 facts:

Because chickens' eyes are more sensitive to light than humans and can detect far more subtle motion, the use of artificial light can lead to pecking within a flock because the flicking of a light bulb that is invisible to us humans appears to them like a rotating disco ball (trust me, being under a disco ball would make me grouchy too!)

I was counseled to use a reddish light for the chicks when I first got them, as they needed its warmth. They also said it would prevent them from pecking at each other so should be left on all the time. It was cool in early June this year here. Then they got bigger so fast I stopped cuz I thought it threw off their circadian attunement and they didn't look the least bit vulnerable. Now winter will soon set in and how to keep them warm without way more expensive space heater elements? On other hand would good enough insulation while maintaining adequate ventilation do fine enough?

Sorry, probably best left for another thread, but?

Thanks, Nick

 

[nchls school]

Hi, In the do you see what I see from the fresheggsdaily site one of the 12 facts:

Because chickens' eyes are more sensitive to light than humans and can detect far more subtle motion, the use of artificial light can lead to pecking within a flock because the flicking of a light bulb that is invisible to us humans appears to them like a rotating disco ball (trust me, being under a disco ball would make me grouchy too!)

I was counseled to use a reddish light for the chicks when I first got them, as they needed its warmth. They also said it would prevent them from pecking at each other so should be left on all the time. It was cool in early June this year here. Then they got bigger so fast I stopped cuz I thought it threw off their circadian attunement and they didn't look the least bit vulnerable. Now winter will soon set in and how to keep them warm without way more expensive space heater elements? On other hand would good enough insulation while maintaining adequate ventilation do fine enough?

Sorry, probably best left for another thread, but?

Thanks, Nick

Hello Nick,

I've been using a space heater for several years; some are quite energy efficient. I have it under a cupboard in the coop so the chickens can't get at it. It is also one of those with an automatic shut off in case ...

Dan

 

[centrarchid]

My chickens see world differently than I do. They have less ability to get about than I do after dark. Their vision up close is very acute where they can detect very small movements within inches of their face and I think they can focus on items at tip of their beak. They also have wrap around vision but depth perception not as good. They see more colors. When comes to distance, most humans are better although my birds can discern hawk species and threat level presented within a hawk species. I can still see hawks better unless they are moving. I can also pick out interesting items from a distance even when they are not moving. Chickens seem to lack the brain side processing to compete when it comes to complex images.


I am pretty sure they can smell a lot better than they are given credit for and employ it when foraging and accessing a given item's nutritional value.

 

[chickengeorgeto]

Chicken and other birds' eye sight is both better and poorer than a humans. Chickens have especially poor night vision and their color vision is non to good either, but it is believed that they can SEE light in the ultraviolet spectrum which gives chickens a completely different view of the world.. There are also two separate areas (foveas) in each chickens' retina that are responsible of viewing objects at different distances. One fovea for viewing objects at close range and the other area dedicated to viewing objects at a distance. This is why a chicken often looks "cockeyed" at strange or new objects. I also doubt that chickens can recognize a member of their own flock from more than a couple of feet away until they can bring the proper part of their retinas to bare on it. This plus a poor memory is why commercial flocks don't erupt into a pecking order frenzy of "bullying"