Road LightingIt's often easier to get close to wild birds while driving than while walking. Sneaking up close to wild birds is discussed in greater detail in the Approching Birds page. But for the special case of approaching birds from a moving car lighting is particularly important.
The daily arc of the sun travels from East to West in the Southern sky. If you're driving a long a rural gravel road in farm country, looking for birds, if you're traveling East to West all the birds on the left hand side of the road will be back lighted. You can stalk those birds and perhaps set your camera to over-expose by a half and F-stop or so. But it's important to know the resulting photographs will be mediocre at best.
You have more options on roads that travel North and South. It's always best to travel heading North, so the sun will be behind you as you encounter interesting birds on the fence posts, or perched on the power poles. If are traveling South and you see a good bird it's best to keep on going. Drive a 1/4 of a mile past the bird and then turn around, so you're facing North again. Your camera will thank you for the effort.
When you are driving and shooting never turn the ignition off and never work the door mechanism within hearing distance. It's best to poke the camera right out through an open window and then to press the camera tight against the side of the car's window opening, so it's almost as motionless as it would be atop a tripod.
One catch-22 problem I've noticed about all this has no obvious solution. Perched raptors often--if not usually--orient themselves facing North, with their backs to the sun. So when you do approach from the South, all you see is the bird's backside. All of which gives new meaning to the idea of "flipping the bird."