decorative bird houses: no, no, no!

I'm discouraged at the number of House Sparrows I see nesting in bird boxes in my neighborhood.  Some of our neighbors have allowed us to put hole restrictors on their boxes to keep the House Sparrows out and allow smaller birds like House Wrens and chickadees in.  People  enjoy attracting birds to their yards and the idea of providing a place for them to raise their young is especially appealing, but they have no idea that putting up a decorative box is creating a House Sparrow factory, which, from an ecological standpoint, does more harm than good.

If you really want a decorative box, make sure it remains a decoration and block the entrance hole.  If you want to host cavity-nesting birds, you should be a good landlord!  Ergo, this Bootstrap Public Service Announcement #1: Tips for Backyard Nest Boxes.

• Make sure the entrance hole is sized precisely for the species you want to attract (and remember, there are a limited number of species that will use nest boxes). For House Wrens it should be no larger than one inch in diameter (any hole 1.25" or larger will admit House Sparrows).  Even better: an entrance slit (one inch tall and up to four inches long).
• Make sure the box is placed in the appropriate habitat for your target species.
• Make sure the entrance hole is positioned the correct distance from the bottom of the box so that nestlings are able to leave the nest.
• Mount the box on a pole to prevent predators access.  Poles may have to be greased or fitted with a baffle to  discourage climbing predators such as snakes, cats, or raccoons.  Place the box high enough so that cats can’t jump on the box.
• Nest boxes must be maintained.  Old nests must be cleaned out of the box after the young have left the nest.  This gets rid of parasites, discourages the boxes from being taken over by wasps, spiders or mice, and eliminates a build-up of nest material that would hinder new nesting attempts.
• Immediately remove nest materials if House Sparrows begin building in your box.  You may have to do this several days in a row.  If they persist, take the box down or move it.  Since House Sparrows are not native to North America, they are not a protected species, and it is okay to remove their eggs or nestlings from a box.

More resources:

• Managing House Sparrows (especially if you have a bluebird trail)
• Cornell's Bird House Network
  • Features of a good birdhouse
  • Controlling sparrows and starlings -- whys and hows
  • Nest box plans
• Audubon's tips for attracting birds with bird boxes
• Nest box plans galore from USFWS

Bootstrap Public Service Announcement #2 is What to do if you find a baby bird.

Comments

[Kris]

We have about two dozen bluebird houses around our property and the only problem we've had has been mice, on occasion. We did pay attention to hole size, for sure. Tree swallows do seem to want to use the bluebird houses sometimes; one year there was quite an argument that went on between a bluebird and a tree swallow--for days!

We have a box for wood ducks also.

We grow birdhouse gourds and like to use those. A wren has taken up residence in one that hangs in an old apple tree not far from the house.

This year we're going to be discouraging barn swallows--last year they built a nest right under the porch roof near the back door--what a mess!

[Patrick]

My aunt had a propensity to give out decorative boxes as a gift. One that she bought looked like a little prison cell and was actually built by prisoners in some New England state. Maybe we can send this info to those prisons...

[Jay]

When cleaning out House Sparrows, it also helps to have no heart.

[Home Bird]

Thanks for the great resources, Nuthatch. I'll put up a link to this post tomorrow. I've seen pictures of bluebirds killed by house sparrows for the nest box, and it's a terrible sight.

[endmente]

thanks for posting this helpful information... I am sending some friends and neighbors to this site.

[Cindy]

a most important post my friend- I would add baffling to the list, to deter racoons and squirrels (that both eat nestlings) and in extreme cases, entrance guards. I'd written a similar post on feeding birds and maintaining nest boxes, will post it sometime next week.
off to Tawas soon- it's pouring buckets!!

[Julie Klein]

How can you discourage Barn Swallows from building nests on the side of the house? It makes such a mess.

[Nuthatch]

The key is to discourage them before they make their nests, because once they make the nests and lay eggs, harassing them or removing the nests is against the law. Seriously.

I'd say if you can't make the surface unappealing in some way (their nests nearly always need both some bottom support and an overhang, so blocking that off somehow with screening would help), then hose off the nest materials a couple of times a day when they start to get them to go elsewhere.

Barn Swallows are native birds that eat flying insects exclusively, and they are great birds to have around, but I get many searches for people looking on how to get rid of them. I will have to do a post on this next year.

[Steven Barrett]

I liked your suggestions for outdoor birdhouses. Very useful and practical.

As a maker of decorative birdhouses, I usually try to implore upon my would be customers not to use these birdhouses out-doors. While vanity might have some impact on my reasons, so does practicality.

After all, since I make my birdhouses for purely aesthetic purposes, the size(s) of the holes I use may not be appropriate for every homeowner's backyard environment.

I do have one question regarding a semi-outdoor purpose for decorative outdoor birdhouse frontboards. They're mostly made from palletwood slats and are designed primarily as momentary resting places for birds; while at the same time offering the homeowner a form crafts artwork to place and hang in his/her tree(s). The holes are mostly rececessed, but all of them have thin pine or plywood (usually luan) backers.

Hopefully this idea, which I received from a close friend, will be bird-friendly as well.
Steven Barrett http://birdhausblog.blogspot.com/