Hawkeye
Birds of prey have a number of adaptations that make their eyesight especially good. The first thing, that is obvious here, is that both eyes point forward giving them great binocular vision for judging distances. Prey species have eyes on the sides of their head giving them all-round vision but the compromise is they have poor binocular vision. Here's a face-on Woodcock, a prey species, showing the different eye positioning: www.flickr.com/photos/timmelling/49683418456/in/photolist Birds of prey also have tube-shaped eyes which increases the size of the image on the retina (a bit like having a bigger screen on the back of your camera). Birds of prey have about five times more receptors per square mm than humans giving fantastic resolution. This is like comparing a 5 megapixel camera with a 25 megapixel camera. The fovea is the part of the eye with the greatest concentration of receptors giving the greatest visual acuity. But birds of prey also have a second fovea in a "pit" which will give an even larger resolution image if they "switch" to using that fovea. Interestingly, Condors which feed by scavenging don't have the second fovea that most birds of prey have, as they don't need such great visual acuity. The Caracaras which feed by walking on the ground also lack this second fovea. And finally birds of prey have a ridge over the eye giving them that fierce look, but this is also critical in protecting their eyes. Look how vulnerable an Ostrich eye is in comparison: www.flickr.com/photos/timmelling/33908387402/in/photolist
This young male Sparrowhawk had just caught a male House Sparrow in my back garden a few days back. I already uploaded a sideways view but this face-on view was dramatically different, so I thought I'd upload it too.
Hawkeye
Birds of prey have a number of adaptations that make their eyesight especially good. The first thing, that is obvious here, is that both eyes point forward giving them great binocular vision for judging distances. Prey species have eyes on the sides of their head giving them all-round vision but the compromise is they have poor binocular vision. Here's a face-on Woodcock, a prey species, showing the different eye positioning: www.flickr.com/photos/timmelling/49683418456/in/photolist Birds of prey also have tube-shaped eyes which increases the size of the image on the retina (a bit like having a bigger screen on the back of your camera). Birds of prey have about five times more receptors per square mm than humans giving fantastic resolution. This is like comparing a 5 megapixel camera with a 25 megapixel camera. The fovea is the part of the eye with the greatest concentration of receptors giving the greatest visual acuity. But birds of prey also have a second fovea in a "pit" which will give an even larger resolution image if they "switch" to using that fovea. Interestingly, Condors which feed by scavenging don't have the second fovea that most birds of prey have, as they don't need such great visual acuity. The Caracaras which feed by walking on the ground also lack this second fovea. And finally birds of prey have a ridge over the eye giving them that fierce look, but this is also critical in protecting their eyes. Look how vulnerable an Ostrich eye is in comparison: www.flickr.com/photos/timmelling/33908387402/in/photolist
This young male Sparrowhawk had just caught a male House Sparrow in my back garden a few days back. I already uploaded a sideways view but this face-on view was dramatically different, so I thought I'd upload it too.