The bird houses and bird feeders are made of all poly lumber and stainless steel fasteners. They are designed to sit on a 4x4 post (not included). The unique bell roof is covered with untreated copper. Bird feeder roof comes off to allow easy filling. Bird houses open up to allow easy cleaning.
On the birdhouse, the entrance hole through which the birds fly in and out are 1.5" wide and 2.5" tall at the tallest point. This is suitable for Blue Birds for example.