Provide ventilation. Drill small holes ƑǞ to 1ǚ_inch diameter) through each side of the birdhouse just below the roof. This will provide better air circulation. Do NOT add perches. Perches allow predatory birds (like jays, magpies, ravens, and crows) better access to the eggs and young in a nest box. In contrast, cavity_nesting birds rarely use perches and prefer cavities without perches.
Most birds that can be attracted to feeders are insect or seed eaters. Insect_eating species, such as chickadees and woodpeckers, are attracted by animal fats or "suet." This can be obtained from the grocery store or trimmed from beef, pork, moose, caribou, or other wild meat. Fats that have a low water content are best in areas with severe cold, because they freeze at lower temperatures. Peanut butter, another fat, also attracts birds to feeders. Its sticky consistency occasionally causes problems for birds, so it should be mixed with melted animal fat and cornmeal or rolled oats. That expensive peanut butter will last longer if it is mixed with other ingredients, anyway.