You should probably clean out all bird houses at least once a year. I like to clean them in the fall after nesting season. But if you didn't get a chance to clean house in the fall you should do it as soon as possible.
By cleaning out a nest box you help deter parasite infestation, a predator’s ability reach a nest and you can evaluate the house’s condition.
It is recommended that you clean out bluebird boxes after each nesting or at least every fall because they aren’t good excavators. Bluebirds just build on top of old nests until the babies are sometimes too close to the entrance hole and fall out before they are ready to fly. A high nest is also easier for predators to reach in and disturb a nest.
Wrens and chickadees can clean out their own box and the presence of a used House Wren nest may actually encourage wrens to re-nest. But you should check to make sure the nest doesn’t have any unhatched eggs or pests. If it’s a mess inside and the drainage holes are plugged go ahead and clean it out. You can leave some sticks below the house to help them rebuild.
To clean the nest box I usually place a plastic bag over the nest and just sweep everything in and twist the bag shut. You can rinse out the house with a water hose or diluted bleach spray. Make sure the drainage holes are unplugged and leave the house open to dry for a couple days. Finally dispose of the old nest in the trash and wash your hands thoroughly.
Whether the same bird comes back to your nest is determined by several factors. Is the nest box clean and still in good condition, did they have a successful breeding season last year, and did they get there early enough to claim the nesting sight again and defend the territory? It’s possible to have the same wren family move in the same house year after year or a wily chickadee or sparrow may spot the house and try to claim it first.
WARNING: Please remove all winter wreaths from your doors. We get calls every spring about birds making their nests in holiday wreaths. Anyone who places hanging plants on a covered porch in the spring or leaves a holiday wreath hanging on the door may find that by April a female House Finch has begun to build a nest in it.
Once a House Finch pair has built a nest in a hanging plant, on a wreath, or over a light fixture, etc., there is little to do but enjoy the experience and wait for the young to fledge (three to four weeks). You can continue to use the door or water the plants but the nest should not be relocated.
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