In cold weather songbirds eat constantly during daylight hours to sustain their energy. At night they expend a lot of that energy fluffing their feathers and shivering to keep warm until sunlight returns. To help conserve some of that energy, birds who nest in cavities or birdhouses during other parts of the year will use roosting shelters in the winter. Unlike birdhouses, which are built to accommodate a single nest, roosting pockets and boxes are created solely to provide shelter in cold weather. Many birds will often crowd together in a single shelter to share warmth.
The benefits of a good roosting shelter include:
Provides a windbreak and traps heat. One study cited a difference of 11 degrees between the internal temperature of a roosting cavity containing one bird and the outside air temperature. A significant difference when you weigh mere ounces!
Provides shelter from harsh storms, freezing rain, heavy snow. Cold is one thing, but who wants to be wet too?
Provides concealment and protection from predators Normally birds would seek shelter as best they could in dense vegetation, thickets, and the interior branches of evergreens. Roosting shelters provide the same protection, but even better.
Roosting Pockets: Constructed of natural fibers, roosting pockets blend into their surroundings. They also have natural ventilation and drainage.
Roosting Boxes: Usually natural wood, these are sturdy, and often have internal perches for more than one bird to huddle up. Most have a door to clean them as needed, and the entrance is near the bottom to be most heat-efficient.
Birdhouses: Some birds have been known to use bird nesting boxes as shelters in a pinch. Make sure this emergency option is available to them by cleaning out nesting waste!
