Background
Although some birds, like American robins, barn swallows, and eastern phoebes, won't nest in boxes, they'll gladly accept nesting shelves mounted on trees or tucked under the overhanging eaves of your home.
Procedure
• Use 2 cm untreated softwood or any wood that resists weathering. This structure can be made easily out of leftover lumber. Never use pressure-treated wood, as it can be toxic to nestlings.
• Follow the construction plan laid out here. Cut the roof, bottom, sides, back, and fence for the nesting shelf.
• Assemble the pieces according to the construction plan, using 4 cm coated flathead screws. The structure will last longer if you secure the pieces additionally with bond-fast glue.
• Either leave the nesting shelf unpainted or treat it with waterproof varnish. If you paint the structure, use subdued brown, tan, or grey, as these colours are more likely to attract birds.
• Mount the nesting shelf beneath the eaves of your house, preferably 4 m or 5 m away from a doorway.
Maintenance
• Remove any nest as soon as the young are fledged. Robins build a new nest each year and often twice in a summer. Removing the first nest keeps adults from building another one on top of it.
• Robins and barn swallows need plenty of mud to build their nests. However, as summer progresses and some birds start to build their second nests, mud may be scarce. See "Provide Nesting Materials for Backyard Birds" for suggestions on how you can help.
• Check on a regular basis that the nesting shelf is mounted securely and is in good shape.