[Gremlin]

Because I like to stay in my car and keep dry (no wet gusset) I use this little attachment to hold the camera. It is very stable and will support the camera even when the 400mm lens is attached, the lens has a tripod clamp so the weight is balanced.

I use a either a two second shutter delay or an app on the iphone which controls the shutter remotely, the iphone screen shows the same scene as the camera viewfinder and avoids camera shake when the shutter is pressed.
OK, it's not much use scrambling through the undergrowth but I leave that to the davemacs of this world.

I also have a monopod which has a rubber grip to screw on to it's thread so it doubles as a walking aid. It was about thirty quids and is worth every one of them.