Use the proper materials. Wood is the best material for birdhouses. Other materials (like metal or plastic) may not insulate the nest enough, so eggs or young could become chilled in cold weather or overheated in warm, sunny weather. Use rough_cut wood slabs, tree sections, or 3ǚ_inch plywood. Never use creosote_treated wood as creosote may kill the eggs or chicks.
Climate Safety: A safe birdhouse is snug and comfortable for nesting birds, without being subject to extreme heat or cold, rainy leaks or damaging winds. To keep a house safe from the weather. Choose a bird house design with ventilation holes in the upper part of the walls to circulate fresh air and prevent the house from getting too hot and suffocating or stifling chicks. If the design does not include ventilation holes, drill unobtrusive holes in the corners or sides of the house. Do not drill holes in the roof, however, where leaks could occur.