I would venture to say most people would not think of putting up a bird box in November. However, if you stop and think about it, it is the perfect time to take on this labor of love.
This is a great idea because cavity nesting birds such as eastern bluebirds, Carolina chickadees, tufted titmice and the like use tree cavities and nest boxes for roosting and nesting. Consequently, by erecting a box at this time of the year you box will serve as a winter roosting site and be available for nesting next spring.
There are rarely enough winter roost sites available for the birds that use them. Take eastern bluebirds, for example. At this time of the year, your neighborhood can serve as the winter home for adult bluebirds that nested this year, their young and migrants from points north.
The ability of cavity nesting birds to find a winter roost site prior to a frigid winter night can be critical to their survival. Those that cannot locate such cover stand the chance of freezing to death before morning.
Some folks even go to the trouble of covering the bottom of the box with a piece of Styrofoam. If you do so, bore a few holes in the Styrofoam for water to drain out of the box.
Another modification you might consider is plugging the box’s vent holes this prevents warm air from escaping the box. If you add a piece of Styrofoam and/or plug the vent holes, remove the insulation before spring.
You can also drill a couple of holes on either side of the box. A wooden dowel can be inserted through the holes. By so doing, you are providing roosting birds with a perch. At the end of the winter, the dowel can be removed before nesting season. Since upwards of 20 or more birds will sometimes roost in a bluebird nesting box on a cold night, the dowel will make it more comfortable for the birds escaping the cold.
If you are curious as to whether or not your box is being used as a winter roost site, simply inspect it for signs of use. If birds are roosting there, they often leave behind feathers, droppings, and sometimes food.
A word of caution: do not check a box at night. Birds disrupted during the night will often stop using the box from then on.
Finally, before putting up a box, place a metal hole guard around the entrance hole. This prevents squirrels from enlarging the hole and ruining the box.