A bird house with easy access makes the job simple. Most bird houses can be opened from the top, the side, the front or the bottom. Boxes that open from the top and the front provide the easiest access. Opening the box from the top is less likely to disturb nesting birds. It’s impossible to open a box from the bottom without the nest falling out. While side- and front-opening boxes are convenient for cleaning and monitoring, they have one drawback: the nestlings may jump out. If this happens, don’t panic. Pick them up and put them back in the nest. Don’t worry that the adults will reject the nestlings if you handle them. That’s a myth; most birds have a terrible sense of smell.
If you clean out your nest boxes after each brood has fledged, several pairs may use the nest throughout the summer. Some cavity-nesting birds will not nest again in a box full of old nesting material.
In the fall, after you’ve cleaned out your nest box for the last time, you can put it in storage or leave it out. Gourds and pottery last longer if you take them in for the winter. You can leave your purple martin houses up, but plug the entrance holes to discourage starlings and house sparrows.
Leaving your wood and concrete houses out provides shelter for birds, flying squirrels and other animals during winter. Each spring, thoroughly clean all houses left out for the winter.
Limiting Predator Access
Proper box depth, and roof and entrance hole design will help reduce access by predators, such as raccoons, cats, opossums, and squirrels. Sometimes all it takes is an angled roof with a three-inch overhang to discourage small mammals.
The entrance hole is the only thing between a predator and a bird house full of nestlings. By itself, the ¾-inch wall is not wide enough to keep out the arm of a raccoon or house cat. Add a predator guard (a ¾-inch thick rectangular wood block with an entrance hole cut in it) to thicken the wall and you’ll discourage sparrows, starlings, and cats.
Bird House Placement
Where you put your bird house is as important as its design and construction. Cavity-nesting birds are very particular about where they live. If you don’t have the right habitat, the birds are not likely to find the house. You can modify your land to attract the birds you want to see by putting out a bird bath, planting fruit-bearing shrubs, including more trees or installing a pond with a waterfall.