No wonder, the great horned owl’s eyes are one of its prominent features. They have big eyes in respect to their overall body size. The owl’s eyes are only slightly smaller than our’s. Obviously the bigger eyes means the wider field of binocular vision. While great horned owls tend to be nocturnal they do become active at dawn or dusk to rely on vision to hunt. However bigger these eyes may be, the owl just can’t move its eyes. They are immobile. But to compensate the immobility they can turn their heads 270 degrees able to see things behind them leaving the body unmoved. Let’s dig out some more facts about great horned owl eyes.
Great Horned Owl Eyes – Can Great Horned Owls See at Night? – How Do Owls See things so Clearly?
The great horned owl has got the biggest eyes of all North American birds. Thus, it seems reasonable to assume that the owl’s eyes occupy much of the space within its skull—leaving very little room for the brain. The eye of a great horned owl almost catches up with the eye of a 6-foot-tall man. But there’s a reason for this.
Nearly all great horned owls have yellow iris. The size of an eye is probably one of many factors that contributes towards the keen eyesight. The shape of the eye has a key role in developing the image in the retina. The great horned owl’s eye is cylindrical in shape rather than the ball-shaped. There’s a reasonable length between the front and the back of the eye—perhaps allowing lens to be at distance from a retina. The size as well as the position of the eye is perfect for hunting at night. The bigger lens means that the owl can absorb as much light as possible. That is how the bird manages to see things even in low-light conditions. Consequently it provides an excellent binocular field of view.
Like in other owl species, the great horned owl’s eyes are so fixed in its bony structure that the bird can only see things straight ahead. But thanks to their flexible neck they can manage to turn heads 180 to 270 degrees without rotating their bodies. Unlike in cartoons, owls cannot swing their neck completely, there’s a limit to their rotation.
Great Horned Owl Eyes – Video
References
Hall, M. I., & Heesy, C. P. (2011). Eye size, flight speed and Leuckart’s Law in birds. Journal of zoology, 283(4), 291-297.
Norberg, R.A. 1977. Occurrence in independent evolution of bilateral ear asymmetry in owls and implications in owl taxonomy. Philosophical Transaction Royal Society, London, Biological Science, 280 (973): 375-408.