bluebird boxes: be a good landlord

THE NEIGHBOR WHO HANGS BAGS of giant homegrown shallots on my gate also has rules and regulations. “Bluebird Rules and Regulations,” to be specific, as in: How to be a good bluebird landlord, minimizing hazards for the beloved birds with specific nestbox tips and tricks.

Deb's bluebird houses in fieldDeb, my “next-door” neighbor despite the uphill mile of dirt road between us, installed her first nestbox more than 20 years ago. Today, she has a trail of 24 boxes on her farm in Columbia County, New York, where she spends much of bluebird season (here, that’s March through August) “worrying over my little charges,” she says.

guard for bluebird boxq&a: deb’s bluebird rules and regulations

Q. Where did you learn to be a good bluebird landlord?

A. I rely heavily on Bet Zimmerman’s website Sialis.org and a wonderful little pamphlet called “Enjoying Bluebirds More” by Julie Zickefoose, and I always urge (implore, really) people interested in putting up nestboxes to read Bet’s page of bottom-line advice for new bluebirders. [Note: Sialia sialis is Latin name for the bluebird’s genus and species. Also: Zickefoose wrote a whole book on the subject called “The Bluebird Effect” in 2012.]

Q. So what’s the basic thrust of your Bluebird Rules and Regulations? 

A. My boxes are installed to encourage successful nesting by the bluebirds by minimizing the many threats they face throughout their season. Before nesting season even begins, I make sure my boxes are cleaned from the previous season.

I also apply a coat of Ivory soap to the ceiling to prevent wasps’ nests, and I attach a bit of plastic netting to the inside of the box opening to serve as a “kerf” (a little ladder that fledging bluebirds can climb to reach the exit hole, photo below).

kerf for bluebirdsThen I do a little dance to bring good luck because, well, you never know.  Last week, as I was rubbing Ivory soap on the ceilings of my 24 boxes, I was thinking how amazing it is that these beautiful creatures survive at all considering the many threats they face while nesting.  Here are a few:

  • Aforementioned wasps’ nests;
  • Blowfly larvae who feed on nestlings during prolonged rains or drought;
  • Raccoons, snakes and rats who steal eggs and kill nestlings;
  • Cats who stalk;
  • Competition from tree swallows and wrens;
  • Nestlings that are unable to climb out of the box at fledging time (necessitating those “kerfs” I mentioned earlier);
  • And most dire of all, the dastardly house sparrow.

Q. What’s the key to success, if there is one? Sounds like a lot of possible trouble can occur. 

A. The most important advice I can offer is to use a nestbox specifically designed for bluebirds, locate it properly and monitor it throughout the nesting season. [Get Cornell NestWatch’s plans for bluebird and other species-specific bird boxes.]

Spring comes, we hear that cheerful throaty song and we are moved to put up a home for the bluebird.  We rush to buy a birdhouse, nail it to a fence post and think we have done a good deed for the bluebirds. If your readers take away only one idea it is this: An improperly located and unmonitored nestbox will quickly become a bluebird death trap.

Q. How do we avoid that?  

A. Bluebird Rule #1:  Resist all temptation to hammer a box onto the nearest tree, the side of a building or fence post. Doing so will almost certainly bring disaster to the bluebirds and heartache to you.

A raccoon, rat or snake can easily climb that wooden post to steal eggs and kill nestlings. Instead, your nestbox should ideally be mounted on conduit pipe that a raccoon can’t easily climb, fitted below with a baffle or predator guard (photo below; predator guards can be made from stove pipe) and located in an open, grassy area at least 100 feet away from shrubs or other natural “cover.”  Nestboxes should face away from prevailing winds, which generally means facing south. If you are lucky enough to have tree swallows, you will want to have a pair of nestboxes, back to back, about 15 to 25 feet apart (like in the top photo).

guard 2 for bluebird houseThen, follow Bluebird Rule #2: Do everything possible to prevent house sparrows from invading. Bet Zimmerman says on her website, “Successful bluebird landlords do not tolerate house sparrows…which are non-native nest site competitors. In my opinion, it is better to have no nestbox at all than to allow house sparrows to breed in one.”

I agree and I think it bears repeating: It is better to have no nestbox at all than to put one up where there are house sparrows, which are invasive alien predators and one of only a few bird species that are not protected by the Migratory Bird Act of 1918. (The European starling is another species not protected by this Federal law, but it is too big to fit into the entry hole of a properly sized bluebird nestbox. The house sparrow, on the other hand, is smaller than a bluebird and can easily fly into the box.)

Q. What are signs of house sparrow invasion?  

A. The first is a trashy-looking nest that includes weeds, straw, and garbage in a big arc curving up the back of the box. The second–and most disturbing–sign is a dead bluebird inside the box. If you find a dead bird inside the box, chances are very, very high that it was trapped and killed by a marauding house sparrow. Bet recommends a number of ways to manage house sparrows.

Q. So besides proper siting, the right box, and reckoning with house sparrows, what other care is essential to being a good landlord?

A. Bluebird Rule #3: Once erected, monitor your nestbox. To quote from “Enjoying Bluebirds More:”

“A bluebird box put up and never monitored is like a letter never sent.”

In addition to monitoring for house sparrows, I also watch for blowfly larvae, which suck on nestlings during prolonged periods of stressful weather conditions like drought or rain. I even keep a spare dry nest on hand to swap out if a nest gets wet or infested (but I admit I do not recommend this for the inexperienced bluebirder).

sparrow spooker 2I also watch very carefully for the first bluebird egg. Once that first egg has been laid, nothing will keep the female out of the nestbox, so that is when I put up a sparrow spooker (above and below)–basically a stick with lots of reflective streamers hanging off it. The flapping, blowing streamers scare the house sparrows and deters them from entering. (If I were to put up the sparrow spooker before the bluebird lays her first egg, she too would be deterred from using the box, so I only put it up after that first egg is laid.) Really good instructions for making a sparrow spooker are here.

sparrow spookerQ. Beyond the box regimen, are there other rules we need to follow?

A. The last (but not least) important advice I have is really up your alley, Margaret, and that is to create a backyard paradise by planning and planting for bluebirds.

To quote again from “Enjoying Bluebirds More:”  “What use is a bedroom if there is no kitchen?”

Bluebirds, like all other wild species, are under increasing pressure from habitat loss. Planting fruiting trees and shrubs helps the bluebirds thrive year-round. Because bluebirds have a fondness for ground-hugging prey, every time we mow our lawn, we create ideal foraging conditions for bluebirds. Water is also a great lure for bluebirds who love to bathe, even daily.

Q. Any last words?

A. Nothing makes me happier than seeing fledglings leave the box for the first time. I wish all of your readers great success in their careers as bluebird landlords. And, may all your blues be birds!

extra: why are bluebirds blue?

WHY ARE bluebirds blue? The obvious answer seems to be, “Because they have blue feathers,” but that’s not it, says a segment on the public-radio show BirdNote. It’s all about the feathers’ structure—and the light trick they create right before our eyes. Listen in to learn what’s going on. (Photo by Joanne Kamo courtesy of BirdNote.)

(All other photos except bluebird, above, and top photo of dirty box by my neighbor Deb, used with permission.)

  1. Cheryl Mandler says:

    I was so delighted yesterday to see a pair of bluebirds checking out 3 different houses and then picking the one made of PVC that looks like a birch log. As I continued to watch them, several sparrows flew by and started harassing them. 10 minutes later the bluebirds were gone. I’m getting out the traps today. Silvia’s.org has lots of info. Thanks to your neighbor.

  2. dcs says:

    In addition to the “kitchen” consider providing some dining room chairs as well. Since they like to eat creepers and crawlers, their hunting style it to find a place where they can sit and scan the ground for those things. A bare stalk, snag, or post here and there provide a place from which to observe the area and spot their preferred food items. Manicured yards or regularly mown field are often surprisingly lacking in such perches.

    On a slight tangent, when I was a kid I put up a bunch of bluebird houses at great grandma’s old farmstead. Grandpa observed the (then booming) bluebird population found year’s mullein stalks to be the perfect height and location from which to nab caterpillars and such. So he went home to his house in town and put a couple of metal fence posts in his extensive tomato patch, set about 4′ high just like the mulleins.

    Although bluebirds weren’t particularly common there (due to the plague of house sparrows), cardinals apparently use the same hunting method. He claimed that after putting up the “bird poles” he never expended an ounce of effort to control tomato hornworms ever again. Once those cardinals had a convenient hunting spot close enough to spot them, the hornworms rarely got large enough to do any serious damage. Since they were just metal fence posts, they were easy to rotate with the crops each year.

    1. Deb says:

      Excellent advice to provide “chairs” in the dining room. Perches in and around the bluebird’s backyard are much appreciated by the blues.

  3. Kristina says:

    Such a timely post! I was just nagging my dad to help me construct blue bird houses, but after reading this I don’t know if I would be able to handle the potential heart break.

  4. elayne dix says:

    My neighbor has had bluebirds nesting between her house and a quiet road( about 40 ft total area front door to road). Over several hours one afternoon, I watched a bluejay repeatedly go after an emerging fledgling. At first ,I ran to it as the jay was pecking the fledgling in a grasp on the ground. The poor father was going berserk sqwaking and attacking. The fledgling survived the physical assault and was escorted back to the nest by the father. The jay kept up the attacks right to the front of the nest box for several hours. It was harrowing.
    How can we protect the chicks from the blue jays?

    1. Deb says:

      Hi Elayne –

      Very interesting about the blue jays. I have never seen that happen despite having a very healthy population of jays here. Knowing just a little about bluejay behavior, it is possible that it would help to place the boxes very, very far from trees. Bluejays like a tall, branchy tree for landings and take-offs. They might not take so much interest in a nestbox that is located far from big trees.

  5. Jeanne says:

    After a snake got around this kind of baffle, we found another way. I bought a box of the tack strip that is used to put down carpet. It is in 4″ lengths and has very sharp tacks on it. Be careful, you will bloody yourself if not. We use 4 strips around the post, tie them on with zip ties. We have never had another issue with anything. The cat will put her paw out and touch it to test and then walk away. No snakes, coons, cats, anything.

  6. Linda Hall says:

    I live in California, and have had a bluebird house in my yard for close to 4 years. The first year we had heavy rain after the nest was built, and I only saw one chick fledge. After opening the nest box, I saw 2 dead chicks with a mass of blowfly larvae…it was so sad.
    This year, due to our early spring weather, the bluebirds built their nest early….and we had rain …..a few days of it. The weather is now warm, in the 80s, but we may have a little more rain in the future.
    There are now 3 healthy looking chicks in the nest, but how can I tell if there are maggots below? The lower part of the nest seems damp….but I don’t see how I can check the chicks for maggots without removing the whole nest, and picking up each chick.
    The dead chicks from the first year we fairly well feathered, so their death had to be a long painful process. I don’t want that to happen again!!

  7. Valery says:

    This is great information, thank you so much. I live in Metchosin, a rural district in British Columbia, Canada, and the last sighting of a bluebird was two years ago. Bluebirds haven’t been established in the area since 1965 and I’m a member of the Western Bluebird repopulation initiative. We have a few pairs living up-island and are hoping, eventually, to coax a growing population south to our area. I’m going to check out the website for sure and thank you so much for the information.

  8. Carole Clarin says:

    Oh dear! I am over 100 miles away from where we put our first bluebird house this past fall, getting instructions from a more experienced bluebird lover. I will be driving there at the end of next week and hope and pray I am not too late to remedy the situation and follow your rules. Thanks for the wonderful advice.

  9. T Melton says:

    Thanks for all the important information, some day when I do not have my stalking cat, I’m going to give protecting blue birds a try.. I have my blue bird house plans ready.. But I don’t want to wish any bad on my buddy Boo the feral – tamed cat buddy!!

  10. Corinne says:

    I have a big problem with barn sparrows, thank you for the information and links.
    Will be trying everything you have suggested.

  11. And I just got a bluebird house for my birthday last week. What perfect timing! After reading this, though, I question whether it’s appropriate for my suburban plot. I don’t think I have a workable spot that’s 25 feet from anything else. I had a lovely pair of bluebirds alight on one of my bird houses several weeks back and I was so looking forward to trying to attract them back. Snakes and sparrows make appearances here as well, though. Should I return the bluebird house???? :-(

  12. Henry says:

    I know it’s spring when the bluebirds return. I have 2 boxes on my property and the birds return every year. However this year they have taken a fondness to my truck. I guess during mating season they defend territory more, so they see themselves in the side windows and mirrors and like to scare away (themselves) other intruders.

    They don’t crash into the windows, just fly about, squawk and then rest on the side of the door. Well they rest and use the door as a “restroom” I’ve had to daily cover the windows with towels and turn the mirrors inwards. Or it’s daily wash the truck.

    I do enjoy these birds especially when they are nesting about the box.
    I guess with a little patience the hormones will die down and I’ll get my truck back. Oh I did try moving where I park the truck, they found it.

  13. Patricia says:

    A few years ago my husband and I were one of the teams of bluebird monitors on The Holden Arboretum’s (Ohio) several trails. During nesting season the trails are checked twice a week for activity. As a matter of course, when the babies are five days old, the nests are always changed, although people can’t make as nice a nest. As each baby is but back into the fresh nest, it is inspected for blowfly larva. If any, the larva are removed (and counted for records). Again, at ten days, the bander tends to banding each baby and again changing the nest out. Not to worry about handling the babies, the parents may fuss overhead and dive at you, but they never abandon their babies. Yes, the poles have the predator guards also and sometimes spookers. (Some nests were notorious for sparrows – location). I had to stop putting up houses at my residence because of the nasty, nasty sparrows. The damage they cause is not pretty. Happy Blue Birding.

  14. Kimberly Reilly says:

    I’m embarrassed to say this, but I’d never seen a bluebird until this article urged me to Google the word…what a glorious little bird! God Bless Deb and all those who work so hard to assure a safe home for these lovely little creatures. I’m wondering if Deb has managed to take any photos of her little tenants.

  15. tracy grimm says:

    I was horrified a couple of years back when my older brother took drastic steps to get invading species out of his bluebird boxes. I guess I owe him an apology.

  16. jane ireton says:

    Last summer we moved about 90 miles north in NC and hope new bluebirds will find and nest in our bluebird houses as they did before. Beautiful birds and fun to watch as they nurture their young, teaching them all their “how to’s”.
    The Vegan cookbook sounds wonderful and it would be a joy to win and cook from it.
    Thanks for all the information that comes my way from you.

  17. linda williams says:

    I didn’t know not to put houses on the trees! Nothing has nested yet so ill move them to poles w predator prevention devices

    1. margaret says:

      It’s a great tip — not to place them on trees. I think many of us didn’t know that, Linda. Nice to see you; thanks for saying hi.

  18. Kathy Sturr of the Violet Fern says:

    Such great advice! I have too many house sparrows to encourage bluebirds here, and starlings. I am in a village so these birds rule. I don’t mind the hawks coming through now and then, though. But I do mind the feral (?) cat! Any advice on how to deter cats from my garden? I don’t have any rights, or I should say there aren’t any leash laws for cats.

  19. Ray says:


    The North American Bluebird Society is another great resource for info on helping bluebirds. I manage several trails in Wisconsin (totaling 65 boxes) and I think the number one concern in attracting bluebirds to a nest box is good habitat selection: open country with scattered trees away from buildings. The subdivision dweller should not attempt to put up a nest box unless they have at least two acres (not wooded) or border on parkland, farm fields or a golf course. If these conditions are not met sparrows and wrens will rule the boxes.

  20. Linda Mauro says:

    Thank you for the great bluebird tips.We have 1 and 1/2 nest,I think one is a dummy nest,no eggs as yet.We had 9 blue birds winter over this year,fed meal worms and heated water dish,it was so much fun to watch them!

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