I made two of these (different design) for my daughters. This one is made in Pine and Oak Trim. I burned the wood using a Shou Sugi Ban technique to help with rot, then dyed the wood in the 2 colors shown here, and applied spar urethane as I'm a belt and suspenders kind of guy. I used a barrel stave-like design on the roof with steam-bent oak to give it a cask-like appearance. Making it into a barrel shape allows room to accommodate the webcam. I made the roof detachable from the inside, which can be accessed through the side door in case I ever need to service the cam. The hole (and overall nest cavity) is sized for small birds, such as Bluebirds. A hammered sheet metal predator guard surrounds the hole. Going down into the nest, there's grooves cut to provide a "bird ladder." A wire mesh provides support for the birds to build a nest (for which my grandkids seem to have put in a few pebbles). The space below the mesh accommodates air flow, and on the floor/base of the unit I've drilled some holes for drainage and ventilation. Lastly, I made a tree mount bracket in Eastern Red Cedar, which I finished with spar urethane to keep it from fading in color as the cedar is fairly rot-resistant.
I bought the embedded webcams from a company called Green Backyard. The webcams have day/night viewing capabilities, for which you can see one of the pics I just captured this morning at O' Dark 30. It's still early in the season for nesting here in New England. The cams are powered by a 24 VDC with a 30' cord (which you can extend by buying one or more additional cords, or you can go with a a long outdoor extension cord. They also require access to wifi, so they need to be mounted within the proximity of a home's wifi range. A free app allows you to view the webcams anywhere/time, and you can even get audio (and a mic if you want to talk to the birds, I guess). They're great for their kids to see and appreciate nature close up.