I've noticed that when I'm out driving I see lots of birds close to the road. I can pull up quite close and usually they don't seem alarmed and go about their business but open the car door and they are off.
So it seems a clamp that can be quickly attached to the car window may be a good option to get some shots that I'd otherwise miss.
I have an old Nissan Patrol with flat windows that are quite thick, so I don't think the weight would be a worry.
Just wondering if anyone has one and how you rate it.