Determine the approximate arrival date of purple martins in your area. Purplemartin.org has a scouting report providing dates by state. Arrival dates range from December in Florida to early May in North Dakota.
Erect a purple martin house at any time of year. The chances of attracting and maintaining a colony increase if the housing is available during the spring and summer months, at least through August.
Situate replacement purple martin housing close to existing structures in which the birds are already nesting and breeding. They are more likely to recognize it as a friendly nesting site next year.