Apr 15, 2020 | Featured in: Watching Backyard Birds, April 2020

Bluebird Boxes and Spring Housecleaning

A western bluebird flies into a backyard nest box.

To clean or not to clean last year's nest from a bluebird box in preparation for nesting this spring—that is the question.

Research shows that bluebirds, when given the choice, overwhelmingly select boxes with an old nest in it. This goes against a popular thought that bluebirds avoid old nests due to parasitic blowfly larvae. Blowflies lay their eggs in old nests, and the larvae attack the young birds.

However, researchers say that although there is a much greater chance of blowflies in boxes with old nests, there is also a much greater chance that parasitic wasps will lay eggs in the old nests. The wasps prey on the blowflies, limiting the damage they do. The researchers also point out that bluebirds might choose boxes with old nests because the birds spend less time and energy finding nesting material.

But neither of those reasons justify failing to monitor, maintain, and even clean your nest boxes. Removing an old nest removes mites, other parasites, and feces, as well as blowfly eggs. Watching Backyard Birds recommends emptying and cleaning your nest boxes soon—before nesting season starts. Remove the old nest; sweep out residual waste material, and you're done. Do not use pesticides or cleaning solutions in the nest box. Harsh chemicals can leave residue that may harm birds, especially nestlings.

What do you think? Tell us!

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  • That doesn't address my concern about the bird houses. I'm on a tiny piece of property (40x100) so there's not much room to plant a heck of a lot or places birds could put nests once the bird houses are gone.
    by Linda DiPierro, Mon, 25 May 2020
  • Plant some native plants in your yard that will attract pollinators and produce berries and nuts. There should be a local society that has a list of recommended plants, shrubs, and trees.
    by Ladylanita, Mon, 25 May 2020
  • Same concerns here. See above post. For your situation I would consider planting a few native plants that will naturally produce berries and seeds that the birds in your area need to survive. Try planting some that will yield foods for all seasons.
    by Ladylanita, Mon, 25 May 2020
  • I've thought about this myself. One thing I considered doing is leaving behind some bird food and a gift card to my local wild bird store with a note asking the new homeowners to please continue feeding the birds. Don't know how well that work but it's worth a try.
    by Ladylanita, Mon, 25 May 2020
  • thanks for the article. I believe that I may have spotted my first hairy woodpecker this morning. we see the downy woodpecker often. it's small. the hairy woodpecker, when compared with the downy, is HUGE. also, the downy feeds at the feeder like most birds--standing upright. This bird, because of its size, hung from the feeder perch with most of it's body below the feeder--like the red belly woodpeckers that we see often. we live is strasburg va. is it possible that we saw a hairy woodpecker this morning?
    by PEretired, Sat, 23 May 2020