I've thought about it, but then again I'd assume it could need some light to be decent to use and I'm not sure if the light could disturb the birds. Would it? Wouldn't it?
It could be cool though.
It could be cheap to make something myself, but then again the energy would be the problem. There are some battery powered webcams which would be easy, but then again I'd have to invest more in them if I'd want to get a decent one..
But when I'm rich, I'll make a ton of those.