Bird of prey vision, distinguishing prey (1 Viewer)

I'm wondering if anyone could help point me in the direction of how I can learn more about bird of prey vision. I'm curious as to how they distinguish prey items from high up. I'm mostly interested about their predation upon snakes. Inparticulary how they see a patern of a snake while in motion.

A little back story to this. There is a poplation of snakes out here in the northern central valley of california that I believe could have evolved in their pattern to help them escape from their avian predators. The species of snake is the california kingsnake, which is typically banded. The valley floor animals are comprised of many abberantly patterned individuals. the typical bands have broken up into a series of stripes, dots and dashes along the dorsal. In addition to their pattern differance, the coloration of the valley kings are much darker with an increased amount of melanin.

I've been trying to find information on how their pattern and coloration could help them escape from raptors in the area.

Hi David I see this is your first post so may I welcome you on behalf of all the staff and moderators at Bird Forum.

That's a very interesting question and I'd love to know the answer to this as well.

D

One important consideration for Raptor vision is that the head can be held surprisingly still even in a bird that is hovering, where the rest of wings and body is going up and down.

Second point is one I am not completely sure about, but when I was a child, I was told that the vision of for example eagles was 7x better than ours, so that the details they could see would correspond to the image we see through a 7x binocular. In other words, if you want to get close to seeing what a raptor sees, try climbing a fire-watch tower with a pair of binoculars, and look down. It may not be the whole story, because some species of birds have vision in parts of the spectrum beyond what we can see.

Overall, I see nothing wrong with your hypothesis that raptor predation could be the driving force behind changes in coloration of a reptile. If that is the case, the coloration would have to fit with the colors of the ground and vegetation among which the snakes are found, so a difference in ground colors would support your hypothesis.

I unfortunately do not have a book in which raptor vision is discussed. A search on the Natural History Book Store (http://www.nhbs.com/catalogue/search ) produced two books that I think might help you:
The Raptor Almanac
A Comprehensive Guide to Eagles, Hawks, Falcons and Vultures
Scott Weidensaul
Lyons Press
Softcover | 2004 | £21.95 | approx. $42/€33 add to basket
Raptors Worldwide
Proceedings of the 6th World Conference on Birds of Prey and Owls
RD Chancellor and BU Meyburg
WWGBP Returns Dept
Softcover | 2004 | £39.95 | approx. $77/€60 add to basket

And several other pages with results that I did not check.

Hope this helps
Niels