Ilcoyote, I'd say that's more learned behavior. Evolution would be more of a physical change. For example, mule deer haveenormous ears - and I'd be willing to bet that's a direct result of thousands of years of predation upon those individuals who can't hear as well.

Were deer always nocturnal? If not, then I'd think it's fair to say that increased night vision is an evolutionary change, which is possible.

But, a deer who can see well in both daylight and dark, learning to travel primarily at night - that's an example of a deer learning to adapt to survive - just like the developed habit of "looking up." An evolutionary change is something that can't be "learned,"like growing bigger ears or the ability to see in the dark.