When: You can add housing to your colony site at any time, even during the nesting season.
Where: There is no set distance apart the new housing should be from the existing housing—10-15 feet apart is enough space to easily manage both systems. Farther apart is fine as well.
What: The new housing may be similar to the existing housing or it can be completely different—as long as it meets the Purple Martin housing standards. Don’t be alarmed if the martins don’t nest in the new housing right away, it may take a full season before it’s active.
Why: More Purple Martins! While having more martins at your colony can increase enjoyment it can also increase management time. Only house as many active pairs as you can properly manage.
Ideally housing should be replaced over a two-year period. Because Purple Martins exhibit site fidelity, returning to the same colony site every year, drastically changing housing from one season to the next may result in site abandonment. Unless the replacement housing is identical, and erected in the same location, the best solution is to erect the new housing near the old for an entire season. Do not replace or eliminate the old housing until some of the martins have accepted and bred in the new housing.
Landlords with several active housing systems may replace a house between seasons without risk of colony loss.
Keep Your Housing in Good Repair
In the fall, remove nests and scrub housing with a 10% bleach solution (1 part bleach to 9 parts water.) Rinse and air dry before storing or closing for the winter. Take care of any needed repairs now, so you won't be caught unprepared next spring. All types of housing will last longer if stored indoors over the winter. If housing is left out, however, cover the house or plug the holes, otherwise House Sparrows and starlings will claim them in late winter and will be hard to dislodge next spring.