DO NOT GET A D800E from Wild Life Photography.
The increased MP will give you amazingly sharp, out of focus pictures, 8 out of 10 times of the images you do capture, and a pile of frustration on the images you miss.
I have a D800 and I have been using it for wild life since it was introduced, although I had to wait to get it.
On static shots in perfect light, nothing beats this camera (well, when it first came out). In studio, this camera simply sings! For sports, action, wild life photography, I will say it bluntly, it is GARBAGE!
The AF is too slow. This is a huge problem.
The sensor gets fooled too readily on certain types of light. This is so annoying, especially when you have that magical early morning light and you push and push and push that shutter button and it simply won't trigger. In many cases, the AF simply won't lock on and you miss the moment.
See the EGRET image below, you have no idea how much I struggled to get that image. It simply could not deal with this light!
The buffer in the camera..... BLOWS!!!!!!!!! You fire a burst, the buffer quickly fills, and you .... WAIT. You know the U2 song .... lyrics ... "On a bed of nails she makes wait, and I wait ... for you" That is exactly what it feels like. When the buffer is empty... the ACTION IS GONE!
The D800 is heavy. Add a big lens and tripod and any other accessories and you are lugging around 20+ lbs. No big deal the first hour.... try 3-5 hours in the field hauling this around and it starts to get heavy and you get tired and cranky.
When you nail an image with the D800, it is very satisfying. However, it will cost you approximately 50-100 images of effort to get that one nice shot, after so many other missed opportunities.
My advice, DO NOT GET A D800E for Wild Life.
I would go with the D500 first! This is simply an amazing camera, it is light, it is fast, the sensor is excellent and it is designed for Sports and Wild Life. The D800 is a studio/landscape/still life camera. You can review a lot of my work with the D800 on 500px, my account is here:
www.500px.com/Art_L
I also have posted a lot of D800 images here on Nikonites, you can view my work with the D800 here:
http://nikonites.com/d800-d800e/8996-my-favourite-d800-images.html#axzz4HUQGzd4f
Just remember, I have taken 40,000 + images on my D800 to be able to show you these samples! As much as I love the camera, it is not a sports/action/wild life camera, if that is your primary need. You will be much more satisfied with a D500.
If you have to get a D800 camera, get the D810, it is more improved, but I would think only marginally so. In speaking with Nikon, the rep told me that the AF and buffer have been vastly upgraded. I have not tested it to give a valid opinion but I suspect it is a marginal upgrade.