In this project, I have put together a nest box camera system for observing small cavity nesting birds. I started with a Texas Bluebird Society Nestbox which I acquired from TBS. I am also building an owl box on the same basic plan, just changing all of the dimensions.
We applied several tricks to keep house sparrows out. We screwed in small eye-bolts around the top and next to the front hole. Through these we strung mono-filament fishing line. This is supposed to discourage the sparrows. After putting this up, no more house-sparrows have entered but other birds have ... fingers crossed.
We mounted the house on a 10ft 3/4" EMT conduit partially buried in the ground in a cement footing. This puts the bottom of the house just above my eye level. I can easily maintain the box with a foot stool. In retrospect, 1" conduit would have been better as this still gets blown around in a breeze a bit (the recommendation online was 1/2" conduit, which we thought would make the birds seasick!).
We used an 8" stovepipe vent and cap to construct a "predator baffle". It rides on top of a worm-clamp fastened to the main pipe just under the stovepipe vent cap. It does clank a bit in the wind, so we may add some foam to reduce the noise.
In order to observe the birds inside the nest, I purchased a Hawkeye Nature Cam and mounted it in a separate box above the main nest box. I started by drilling a 2-1/4" hole centered on the top of the nestbox roof. I then created a 4"x2"x2" box out of red cedar board in which the camera is housed.
I removed the sun-shield from the camera and flipped the bracket around, mounting first on a piece of corner molding.
This made it easy to then screw this completed assembly into the inside of the camera box
I need to add some weatherstripping or caulk to improve the seal between this box and the roof of the bird house, as the Hawkeye is not weatherproof.
In order to capture action outside of the bird house, I mounted a Swann Pro-642 security camera on a 10ft 1" EMT conduit pole fixed in a movable footing of concrete. I placed this a few feet away from the side of the bird house. I am hoping squirrels do not defeat the predator baffle by jumping across this gap. What I really need is a night vision camera with a narrower field of view so I can place it further away.
In order to capture all of the action of these cameras, and the ones I will set up for the owl box, I purchased a Lorex LH030 Internet-enabled DVR. I installed it in the observatory, which is much closed to the nest boxes than the house, and remotely attach to it with a PC or iPad client. The client is a bit... quirky, and we're still trying to figure out the best way to download video. Right now, it seems easiest to use the playback mode and then record with a screen-casting application such as Camtasia or Jing.
Update 2015-03-21 - Last night, the camera in the owl box failed. I think that water got into the in-line filter mounted on the cable near the camera. The warranty support from Birdhouse Spy Cam where I purchased the camera is a full year. Richard Yost, owner, was quite ready to send me a replacement camera - awesome service. In the meantime, in order to try to fix the problem, I took the camera down and heated the cable in a heating pad with a desiccant bag to drive out the moisture. After a hour of this treatment, I was able to recover the video and audio feeds. I have changed the mounting arrangement and place the filter assembly in the wooden housing as well.
Here is how the camera looks from inside the big owl house. The view from the bluebird box should be similar albeit with a smaller size ceiling.