You might want to check with wildlife rehabilitators in your area and see what types are in need, and if they are seeking suitable release sites for the sorts of birds you are looking to provide nest boxes for (
local vets/animal control/conservation will likely point you in the right direction). I always look to the Audobon society for bird house plans - they even have a book...
A few thoughts for more successful nest boxes:
Not all birds like or what circular openings; swallows like an elongated (left to right) oval; others like an up/down oval.
Cavity dwellers (chickadees, etc.) "excavate" their homes, so place a few inches of
wood shavings in the new home for them to "create" their new home.
Place homes at the appropriate height and the appropriate location (open/forested/marshy area) for the species you are interested in.
Always place homes facing away from prevailing winds, but facing east, if possible (they like the early morning heat as opposed to evening heat).
Place homes where they are protected from predators. Building mounted homes keep climbers better at bay; tree/pole mounted homes amongst the
trees keep the birds of prey from snatching them to-ing and fro-ing from the nest.
If pole or tree mounting, consider using anti climbing baffles (strip of metal around trunk five feet up, section of stove pipe on smaller trees) to ensure climbers like squirrels, weasels, mink, etc. cannot access nest boxes.
If you are in a very warm climate hole sizes may need to be increased; if in a much cooler climate hole sizes may need to be decreased (smaller versions of some species in cooler climates, larger versions of some species in warmer climates).
Do not place bird of prey (owl etc.) boxes and songbird nest boxes in the same locations.
Make sure the species you are interested in are compatible and not competitive or cannibalistic types.
Provide appropriate food sources, but a distance away from the nest boxes to ensure their privacy and security.
Rough up the interior wall so that the young birds have something to grip to when ready to climb to opening.
Pet or human hair from brushing;
dryer lint; twigs, grasses etc. are all helpful nest materials to supply.
A few mistakes commonly made in the construction of bird homes:
All nest boxes must have a narrow gap at the bottom, in case of
water needing to drain.
All nest boxes need a ventilation slot along the top, under the roof to allow for excess heat to escape.
Ensure the roof is OVER top of the walls and not inset, or you will have a leaky box.
Where ever possible, leave a generous overhang on the sides and especially on the front - down sloping (over the access hole) is generally better than a peaked roof style.
Make sure you allow an easy way to open and clean the home - unless cleaned out seasonally, they are often not reused as they can become infested with parasites.
Ensure you have thought out how you will mount them and where - it can be very awkward to mount a fully built home through the "door".
Please, never put a "perch" on the front - this provides support for nest raiders to attack the home.
Please, never paint or use any sort of chemical preservatives (NO PRESSURE TREATED WOOD), these are commonly very dangerous for birds who are extremely sensitive to chemicals.
And lastly, please, please, please, do not put up feeders or nest boxes if you have outdoor cats - most fledglings learn to fly from the ground up and spend anywhere from three days to three weeks on the ground learning to fly....
https://www.spokaneaudubon.org/page-280285
http://www.sialis.org/nestboxguide.htm
http://ravenview.com/blog/2009/04/27/a-bird-house-specification-chart/