In previous years my birdbox camera was just a USB webcam in the birdbox. There was a modified network cable passed into the house, and thence on to the camera server (http://icamview.co.uk). This worked pretty well, but was limited in what I could do with the images / video from the server. - This was what spurred me to use a Raspberry Pi, and it's camera in the birdbox for this year. - The problem however was that when I put the Pi in the box, and powered the other end of the (10M long) USB cable, the voltage at the Pi was not sufficient for it to run in a stable manner.
The way I've addressed that is to use a 12volt supply in the house, and use a 12V->USB adaptor in the birdbox. - For the princely sum of £3 including postage, I got three of these cigar lighter adaptors:-
These supposedly provide 5V at 1A which should be more than enough for the Pi, with the camera, lights and network adaptor. I modified the cigar lighter adaptor to take the input power feed with a wire and so there are no external connections. Here it is in the birdbox. As you can see it's pretty cramped in the 'camera' compartment of the box with the Pi, camera, power adaptor and leads. The whole is held loosely in place with 'blu tak' which seems to work more than adequately.
The 12V power supply I took from a rubbish router which my ISP (TalkTalk) sent me. I also replaced the 'network' cable with the rather over engineered cable you see here.
Anyway - lid back on the box, mounted back on the wall and has all been working fine since. - No birds yet though!