As colder weather approaches, I often get questions about winter roosting boxes.
Many cavity-nesting birds roost (that is, sleep) in natural cavities, nest boxes, or specially designed roosting boxes. It sure beats sleeping out in the open on cold winter nights.
Bluebirds, chickadees, titmice, nuthatches, and Carolina wrens nest in cavities and readily use nest boxes, but they also sleep in natural and man-made cavities on the coldest nights of the year.
On frigid nights, a cozy roost site can mean the difference between life and death for cavity-nesters.
You can make winter more bearable for these birds by building or purchasing a roost box.
Some observers have reported as many as 10 bluebirds cramming into a nest box at dusk in mid-winter.
I’ve personally seen as many as a half-dozen bluebirds retire to a nest box on a cold winter evening.
There are also reports of as many as 46 winter wrens, 50-plus pygmy nuthatches, and 29 white-breasted nuthatches roosting together in single cavities.
This pattern holds for many cavity-nesters. On warmer nights, they roost in vegetative cover; on colder nights, they sleep in cavities.
Woodpeckers and some owls, on the other hand, usually sleep inside cavities, regardless of the weather.
Roost boxes
Roosting behavior gives backyard birders another opportunity to provide a critical resource for cavity-nesters. But understand that this applies only to cavity-nesters.
Though cavity-nesters frequently roost in ordinary nest boxes, this may be simply because better roost sites are unavailable.
Nest boxes are typically well ventilated; the entrance hole is positioned at the top of the box.
Vents promote heat loss (which is good during the hot nesting season), and the entrance hole allows heat to rise and escape.
Designed to minimize these problems, a roost box measures approximately eight inches square and 24 inches high.
There should be no air vents, and all upper joints can be sealed with a silicone bead to completely eliminate air flow.
The only opening is a two-inch entrance hole cut into the bottom of the front panel.
Inside, a series of shelves or quarter-inch dowels runs from side to side. The dowels should be staggered to minimize the droppings that fall from birds perched above to those perched below.
Finally, be sure one side of the box is removable so it can be cleaned out occasionally.
Enjoy
Hang the roost box five to eight feet above the ground in an open southerly exposure to take advantage of solar radiation, and if possible, place it so it is protected from the prevailing winds.
If you erect a roost box, don’t expect immediate results. Birds need time to discover a new roost site.
Ways to determine if a roost is being used include checking the floor for droppings and watching for birds leaving the box at dawn.
Another option is to modify ordinary nest boxes for the winter. First, remove all old and soiled nesting material from used boxes and replace with a one-inch cushion of dry, insulating grass.
Then plug all vent holes with a pliable, putty-like material that can be easily removed in the spring.
More
Finally, I must add a word of warning. During periods of extreme cold, especially following an ice storm, birds sometimes die while roosting.
This is natural and unavoidable, though it can be shocking to find a box full of dead birds in the spring.
Though roosting boxes have been around for years, surprisingly little is known about how much birds use them. I would love to hear from readers who have experience with roost boxes.
For detailed winter roosting box plans, visit Cornell’s Lab of Ornithology website, www.birds.cornell.edu, and search “roost box.”
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The only place I have to mount a roosting box is above a frequently used door. Will the birds poop in front of/under the roosting box? Much as I love birds, I don’t want to walk through their droppings.
So, I thought they would possibly adapt, informative article… Ive brought down from barn a new unused Wood Duck box, cedar shavings came with. Has large hole (Wood Duck size). 2 batches from same pair have stayed around since last hatching in July. Also parents. Feeling guilty as I treat every week or so freeze dried meal worms. These darlings are the joy of my life. So aggressive when bird brain made up on housing!! Anyway I want to use the cedar shavings, is this okay?? I will put the dowels in as advised. Will have to put on West exposure gable end of shed. Comments please!
I have been experimenting with Carolina Wren roosting sites. This past summer, after nesting season, I discovered a wren sleeping in the top fold of a patio umbrella. During a storm at night he was awakened and perched near his fold. The storm blew the table and umbrella over, and I was concerned and went out after the storm and saw him fast asleep in the fold.
After that incident I attempted to make wren sleeping quarter out of a nylon pants leg clipped to a hanger. It was similar to the umbrella fold in shape, and also soft and open on both ends. It was placed under the porch eave out of the rain and not too far from the umbrella. There is a light on at all times. It wasn’t long before two wrens were sleeping in it every night. I call it the summer house now.
When the nights started getting cooler I offered an assortment of contraptions but none were occupied. I have photos of my failures. However I have two that have both been slept in, one more than the other. It is not conventional. There is no wood. It is a plastic square pop corn tub from the local movie theatre, turned on its side, and filled with the softest yarn, almost all the way to the top. All the top edges are scalloped, so to hold the whole thing together, I wrapped a natural twine around and around in all directions to form a loose webbing. They enter through the web and in about two seconds they some how drill their way down into the soft yarn. I generally can’t see them in there after they are settled. The other acceptable roosting area is a cardboard box, lined with styrofoam, wrapped in bubble wrap and filled with soft yarn. The opening is towards the top. Both of these are hanging under the eave of my back porch on either side of the summer house. I watch for them every evening to see which one they will pick.