Roosting Boxes Help Birds Keep Warm This Winter

Many people are familiar with the nesting boxes that birds use in the spring or summer, but far fewer have thought to place a roosting box in their garden. These provide small birds with critical shelter on cold, blustery, or snowy nights.

Essentially, a roosting box is a sturdy wooden box similar to the more familiar nest boxes but with some important differences. Roosting boxes are quite a bit larger than nesting boxes and can hold many birds. Inside, they are filled with a series of perches or shelves. In a roosting box, the hole is near the bottom of the box to prevent escape of heat from the birds' bodies. Nesting box holes are usually near the top, and there may be ventilation holes as well.

Bluebirds, chickadees, wrens, nuthatches, titmice, and woodpeckers all use winter roosting boxes. These are the same kinds of birds that nest in boxes and in holes (cavities) in the summertime.

On winter nights, small birds seek shelter from the cold and snow in roosting boxes. Inside, they huddle together to share body heat and stay warm. The number of birds the box can accommodate depends on its size. Most birds will use the perches, but bluebirds huddle together on the box floor. If your goal is to help bluebirds, a box without shelves or perches may be preferable.

On cold nights, small song birds expend a lot of energy staying warm by fluffing their feathers and shivering. Though they crowd together to keep warm, in cold climates, hypothermia is a common problem for small birds. Communal roosting in cavities conserves energy and makes it easier for birds to stay warm on cold nights.

You can build a roosting box yourself using some of the many plans available. The Audobon Society of Omaha has plans for a box specifically designed for bluebirds. Yardener offers detailed plans for a roosting box with perches. Roosting boxes can also be purchased online for about $30 to $40. Mine, the Woodlink Audobon Series winter roosting box, is widely available and converts to a bluebird house in the summer.

An entrance hole 2 inches across will allow most small birds to enter. If you prefer to keep out starlings and other aggressive birds, look for, or build a 1 ½-inch entrance hole.

Mount the box in a sheltered area about 6 to 12 feet above the ground. The south side of a building, a pole, or the trunk of a pine tree are often recommended. The best locations are those where the box may receive additional shelter, such as from evergreen boughs, or heat from the sun.