Nesting season is behind us, and birdhouses — nest boxes — will be vacant until spring.
Now is the time to clean the boxes of used nesting material, and to make any needed repairs.
We will assume your nesting boxes are built to allow easy access. Trying to pull old nests through the entry is not worth the effort.
If your box does not have a hinged side or roof, fix that now or buy a new box. Birds almost never use a box containing an old nest.
Empty the box, maybe give the interior a squirt with a hose, and DO NOT CLOSE IT UP. A closed box, in my experience, is too often used as winter housing by mice. They will soak the interior with urine.
Close the box in mid-April, prepping it for use as migrants begin to return.
The size of the box and the entry hole will determine which birds will or will not use the box/house. Find a list of recommended sizes and placement heights for our common backyard nesting species at sialis.org/nestboxguide. (Sialis is the Latin name for Eastern bluebirds.)
The typical bluebird box has an entry 1 ½ inches wide. It will readily be used by chickadees and house wrens. House sparrows could be attracted to these boxes. They will take over, preventing use by other species, sometimes killing occupants to get the box.
Remove the sparrow nest as often as necessary. House sparrows are not native birds.
If you buy a box, cedar wood is best, always unpainted regardless of material. Be certain the entry hole is appropriate. Manufacturers do not always follow best practices.
Buyer beware when it comes to birdhouses.
Bird specialty stores would be a best choice, big-box stores not so much.
Exterior perches are unnecessary. They act as predator ladders. Holes in trees used by cavity-nesting species do not have perches.
Boxes/houses should be tightly built, waterproof. If yours have gaps or cracks, tighten them up. I patch my boxes simply with pieces of wood glued to the exterior of the box. Sort of rough-looking, but birds do not make aesthetic decisions.
Proper placement is important. For good information on appropriate placement of the boxes in your yard, see the Cornell Labs website: nestwatch.org/learn/all-about-birdhouses/nest-box-placement/.
The nest boxes I tend on a nearby golf course routinely get nesting tree swallows, bluebirds, chickadees and house wrens. All are using boxes designed for bluebirds.
In our yard, using bluebird boxes, we get nesting chickadees and house wrens. A pair of white-breasted nuthatches use a tree cavity. We had the unexpected pleasure this year of a nesting pair of great-crested flycatchers. They used a box with an entrance that had been gnawed large by a squirrel.
Red-winged blackbirds, cardinals, catbirds, yellow warblers, common yellowthroats and house finches nest in the brush surrounding the muddy pond in our unkempt yard. We consider ourselves most fortunate.
By the way, we plan to get rid of our remaining yard grass next spring. Half is gone now. The rest is to be planted with a no-mow seed mix that includes white clover and other flowers for pollinators.
Pollinators today need more help than birds.
Lifelong birder Jim Williams can be reached at email@example.com.