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!

comments powered by Disqus

New On This Site

The Latest Comments

  • I understand that the ducks' blood vessel arrangement in their feet is to provide the benefits of the counter-current heat exchanger mechanism; returning cold venous blood from the feet is warmed by the descending warm arterial blood, preventing excess heat loss by the feet and avoiding cold blood from chilling the body. This means that the feet are cold, not warm.
    by Frank Barch, Sat, 02 Jan 2021
  • I have the same situation. The feeder is attached to the middle of a large picture window that goes ceiling to floor w/ no ledge or sill for animals to climb or balance. Yet every morning all the sunflower seeds have been cracked open and hulls left. Any ideas what it is?
    by Liza Fox, Sun, 15 Nov 2020
  • I have a bird feeder that sticks to my window and I've been hearing noises against the window at night right now its going on. But whatever it is it is aware of me. And when I get to window it leaves.I can't imagine a squirrel or mouse or possom being able to get at it. ...So as I was reading this article im to assume no bird eats at night. Or no birds will eat at night. Why is that? Then im also thinking of a sinereo that could a lost confused bird eat at night. This eating thing is watching meI turn out the light go there noise dissappears..Thank you.
    by Nosferatu, Thu, 05 Nov 2020
  • I have metal baffles (cones) on my pole for my bird feeders. Something is still tempting them at night. What else could it be? Deer???
    by Ella Spencer Connolly, Thu, 27 Aug 2020
  • I found where he lives, then I keep him up all day by singing at full volume! Hah, that'll show the little sucker!
    by Pike Juan, Tue, 11 Aug 2020