THE SIGHT OF Eastern bluebirds rates high on my happiness scale, so I say bring them on. But what makes a place look like inviting habitat to these charismatic birds, encouraging them to maybe stick around during breeding season? And if your site meets with their approval, and a pair perhaps shacks up in a nest box you provided, how can you then be a good bluebird landlord?
Those and other bluebird-centric questions were the topic with expert birder Julie Zickefoose, a writer, artist, naturalist and wildlife rehabilitator who lives on an 80-acre wildlife sanctuary in the Appalachian foothills of Ohio. She’s a contributor to “BWD Magazine,” formerly “Bird Watcher’s Digest,” and is also the author and illustrator of multiple books, including “Saving Jemima: Life and Love with a Hard Luck Jay,” “Baby Birds: an Artist looks Into the Nest,” and “The Bluebird Effect: Uncommon Bonds with Common Birds.”
Plus: Enter to win a copy of her bluebird book by commenting in the box near the bottom of the page.
Read along as you listen to the Feb. 24, 2025 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify (and browse my archive of podcasts here).
welcoming bluebirds, with julie zickefoose
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Margaret Roach: So welcome back, Julie.
Julie Zickefoose: Well, it’s so great to hear your voice. Thank you.
Margaret: Yes, yes, yes. Well, I just thought I’ve had enough of winter. Let’s talk about bluebirds [laughter].
Julie: I was out just this morning listening for them on a sunny morning like this. They should be singing and goofing around, but I didn’t hear them. I did hear a singing cardinal, which buoyed my spirits tremendously.
Margaret: Oh. It’s funny, where I am in the Northeast, I do see them in winter, the bluebirds—that is, they sometimes even show up at the feeder for a minute. So I want to talk a little bit about their life history, their life cycle, and so forth. But first I should say that you and I are in Eastern bluebird range. There’s two other native bluebird species, I think, in the United States, the Western and the mountain, I believe. So there’s bluebirds in most places in the country, I believe.
Julie: Yeah, you can usually find bluebirds if you have the right habitat. I wouldn’t call mountain bluebirds particularly common, but they’re there. And oh my goodness, if you’ve ever seen one, they just take my breath away because they’re entirely cerulean blue. The male, just no brown on it. It’s just amazing. And the female is subtly beautiful as well. I have such a fond association with them in New Mexico. I just love seeing them.
Margaret: And bluebirds are thrushes, yes?
Julie: Yes, they are. Yeah, we do have the three species, and mountain bluebird is actually larger than the other two, and actually takes another eighth of an inch on the entry hole of a nest box because it’s so broad-shouldered, it can’t get into a one-and-a-half-inch hole.
Margaret: Oh! Well, we’re going to talk a little bit about nest boxes and so forth and matching the right one to the right bird in a few minutes. So let’s say we’re in the East—and when I say the East, I don’t mean just the East Coast. I mean the Eastern bluebird is spread pretty far into the country, I think.
Julie: Oh yeah. Yeah. It actually crosses the Mississippi and heads on over into the Great Plains.
Margaret: Yeah. So what kind of habitat, if I’m an Eastern bluebird, what am I looking for? What kind of a place am I looking for?
Julie: Yeah, that’s interesting. Lots of people associate them with pastures. Any place where the grass is kept short, whether by animal or by machine, and this is because they’re visual hunters; they’re still hunters. They’ll perch up on a high perch and look for crickets, grasshoppers, spiders, and caterpillars down in the grass. And then they plunge, dive down, to go get them.
If the grass is too long and thick, they can’t see what they’re doing. So the funny thing that goes on where I am is they nest happily in hayfields, but only for the first brood, before the hay gets so high that they can’t see what they’re doing. So they really kind of depend on mown areas or grazed areas. And while a school playing field can be a mown area that they would be attracted to, a cemetery, a golf course for better or worse. So it really is all about short grass for the bluebirds, and open spaces.
Margaret: Alright, good. Yeah, because my uphill neighbor has a lot more open space. I mean, my place is on a hill and it’s kind of tucked in and surrounded by forest edge. And of course I planted a few plants the last 30-something years [laughter]. Oops, sorry.
Julie: Imagine.
Margaret: Yeah, but they’re always here, and especially in the spring, they’ll come and they check out the nest boxes, and they always lose out to the tree swallows. The tree swallows always take the nest boxes. But I know where the bluebirds go, they go up the hill to my friend Deb, because she’s got the perfect spot and she’s got lots and lots and lots of boxes out. And yeah, she’s a great bluebird landlord [laughter].
Julie: So that’s really, that’s your only weapon with tree swallows, is to just put up, saturate the area with boxes and hope they work it out.
Margaret: And I love tree swallows, too. I mean, they’re aerial acrobats and they’re fun. And the noise they make if I head in the direction of a box and they don’t want me to [laughter], it’s like some radar signal or something, some electronic signal. Yeah, it’s crazy. O.K., so that’s what they’re looking for.
And you told us kind of what they eat. So as I said, even in the Northeast, I see them in winter sometimes, but I think people associate them with spring, as if they migrated and came back. But just like people think of robins that way, but it’s not exactly the case. What’s their pattern?
Julie: They are what’s called facultative migrants. So they don’t have a set migratory path that they take every year without fail, the way, say. a Cape May warbler would. A bluebird goes as far south as it needs to, to find food and open water. And what happens here in the mid-Ohio Valley is in harsh, harsh weather, they will desert their normal haunts, which would include my ridgetop, which is a big meadow. And they will go to the water courses. You’ll find them along the banks of rivers where they can forage, where they can find any remaining fruiting plants, dogwood berries and things like that. And so they will repair to those areas when the weather really clamps down. And then on a nice day, a sunny bluebird day as we call them, they’ll commute back on up and start talking about nesting.
Margaret: And that’s a kind of hilarious time. I always love watching, and I think of it as a nest-box display or something. The males will come and they’ll do this showoff routine [laughter] by the nest box; it’s like, “Hey, look at me, I’m handsome. Hey, don’t you want to mate with me?” You know what I mean? It’s this funny, very, very, very showy… and I love watching it. Of course, they would prefer that the female bluebirds loved watching it rather than me.
Julie: Yeah, it’s a great thing. It’s called the wing-wave display [illustration, top of page], and they’ll raise the far wing, not the one closest to the female, and they’ll flap it partially extended almost as if it’s not even connected to their body. It’s just this crazy-looking thing. And I actually did a painting of that, and I’m waiting for a print that I just ordered of that painting of a bluebird on an old, weathered nest box just waving his wing like crazy, because it’s just such a signature sight and sound of spring.
Margaret: So if she says yes, she wins the prize, which is that she gets to build the nest, right? [Laughter.]
Julie: Yeah. Birds, they’re nest site-limited birds. And the nest cavity is the thing. If they can find a good safe nest cavity and it has ample foraging area around it, they are golden. And she’s a lucky girl. It’s hard to find the right kind of nest cavity, and boxes really help that.
Margaret: But she does a lot of the lining of the nest, doesn’t she? She prepares the nest itself within the cavity,
Julie: The whole thing. He will bring bills full of material and kind of stick it in the box, but he doesn’t really do the building. She does all the sort of squiggling down and shapin the cup and all that. And she does most of the work, but then he kicks in as soon as the babies hatch; he helps feed them.
And she’s the only one who’s equipped to brood them and keep them warm because only she forms a brood patch on her abdomen—a featherless area with lots of sort of congested blood vessels that really transfers the heat to the eggs. And the male hasn’t developed that. So I’ve actually, as a rehabber, received a couple of broods of bluebirds to raise because the female was killed.
Margaret: And the male can’t do the job because the feathers are on his belly there?
Julie: Correct. He can’r keep them warm enough. Yeah. Now, after a certain age, if the female is killed—this is kind of morbid—but if the female is killed after the babies are about seven to eight days old, they can survive, because all they need is food at that point. They’re thermo-regulating, they’re feathered, and a male can finish raising the brood.
But this gets to a whole thing for me, which is keeping notes. When you’re taking care of your bluebird boxes, I don’t care how trivial it seems, write down the date it happened because you’ll be so glad you did. I keep a little log book. All my boxes are numbered or named, and I keep a little log book. Every time I visit the box, I note the weather, the time, the date, and what’s happening in the box. And that way, since I know that the incubation period is 12 to 14 days, I know when the eggs will hatch, because I’ve been there and I’ve seen when they were laid.
So I can’t stress enough the importance of writing down in an organized manner what you see in the box, because there are set periods for incubation, and for the nestling period, and a set time when they fledge. And if you know when these things happen, you’re really on top of it and you can kind of be there for the miracles.
Margaret: Yeah. So you said “all my boxes.” So confess, how many boxes? [Laughter.]
Julie: Oh, I run about 26.
Margaret: I’m one of those people who I go to the garden centers and also see online the ads served up to me of these so-called bird houses or nest boxes. And they’re like, I dunno, anthropomorphized—I mean, they’re like pretty houses for miniature doll houses or people houses. Bird houses, it’s a different matter of what they want, the dimensions and the architecture. I love that site, what is it? Nestwatch.org, I believe, part of the Cornell Lab of Ornithology suite of websites, they have All About Bird Houses, the whole section, and it tells you species by species, the dimensions and how to build the right box and so forth.
Julie: Yeah, and it’s pretty specific stuff. And you’re right, there’s a lot on the market that’s just totally unsuitable. Like sometimes you’ll see a really cute a-frame box with the hole right down at the floor level of the box. So it’s got all this space overhead that the birds can’t use, because the entry hole is in the bottom.
So yeah, there’s a great site, North American Bluebird Society, and they have pages with here’s a proper box dimension, here’s what they look like, here’s what you need to have in the box. And I think the single most important thing, after a one-and-a-half-inch entry hole, is that you can open it from the side or the front, so you can get in there and help when they need help.
Margaret: O.K.
Julie: And you can also get in there to clean it out in between broods and should, God forbid, a baby die in there, you can take it out and protect the other babies that way. So there’s many, many reasons to open the box and to be messing around with the contents.
Margaret: In late winter, I always go around and clean out the nest boxes that I have on the property, just take out everything that was in there from last year. I mean, I assume we start clean. Yes?
Julie: Yes. We start clean. And if you are serious about running boxes and taking real good care of the ones in your yard, I recommend cleaning it between broods.
Margaret: Oh. So if there’s going to be multiple broods, O.K.
Julie: Correct. Yeah. So when you see the babies leave, get in there, clean it out, dust it out with like a paintbrush. Sometimes if there’s a mite infestation, I’ll dash it with boiling water, which is a perfectly non-poisonous way to kill all the mites in there, and then leave it open until it dries or swab it out with paper towels. There’s lots of things you can do to make it nice for the next brood. And I think it’s better to clean between broods, because it removes the parasites that can build up over the season.
Margaret: So what about defense against predators? So you’ve got, potentially, these eggs and then these little helpless creatures in there, with Mom looking after them. I see about baffles and I see about all kinds of other sparrow-spookers, these devices to scare away house sparrows. So what’s your predator-proofing involve?
Julie: Yes. So everybody’s instinct when they get a bird box is to nail it up on a tree. And that is the worst thing you can do, for a lot of reasons. It’s like a predator highway. If a raccoon is climbing up the tree, why isn’t it going to stick its hand into the hole on the box? And they will. Earwigs go up the tree trunk and collect behind the box where it’s damp, and then go into the nest. And you don’t want to open a box seething with earwigs. It’s disgusting. There are just so many reasons not to put them on trees, or on fence posts. I only mount my boxes on metal conduit with a stovepipe baffle that is snugged right up underneath the nest box.
And that is something that you can make on your own for probably around 25 bucks. You can get everything at Lowe’s; it’s basically a 2-foot length of galvanized stovepipe with a fitted cap. I usually use a 5-inch diameter stove pipe, and I have a suspension system that you use to suspend it. And what I’m trying to think of is how we can get this information to people who need it. There may be stovepipe baffle plans online [below, from a BWD Magazine colleague of Julie’s], but the most important thing is to make sure that every box you put up is on a metal pole and is isolated from overhanging limbs and is protected by stovepipe baffles.
Margaret: O.K. So that’s critical. In terms of placement, many of us have… You’re in a preserve, so to speak; you’re 80 acres, so it’s a lot more choice of where to put them. But what would be the ideal siting in a smaller place—the most open spot, and as you were saying before, where there’s mown area beneath or alongside or whatever?
Julie: Yes. And most important, they don’t really care exactly where the box is relative to the foraging area. As long as they can get to a foraging area, bluebirds will nest on the woods border and then commute to a nearby hayfield to feed. That’s not a huge deal. But if you’re putting up a box in your yard, the important thing is to keep it at least 15 feet away from any vegetation, shrubbery, anything like that, that a black rat snake or another predator could use to sort of hitch over onto it.
So in other words, you don’t want to put a box under a tree with overhanging limbs. That invites predators to climb down onto it. See ,what you’re doing when you’re putting up a box is you’re putting up kind of an ad that says, “Hey, there’s candy in here.” [Laughter.] It’s pretty obvious; any predator that is paying any attention at all can see the birds going back and forth feeding the babies. So you’ve got to… you owe it to them to make sure you protect it and make it hard or impossible for predators to get to it.
Margaret: How high is the box on the pole?
Julie: Well, I usually put it so I can just see into the nest. So I’m 5-5, so my eye level and a little above, the higher the better. And I say that through hard experience. I have these 5-foot pole mounts. And what has happened over the years—I’ve lived here for 34 years—is the black rat snakes have gotten old and big [laughter] and they are now 6, 7 feet long. They are enormous. So what’s happened is some of my boxes are actually short enough so that the snake can coil itself around the metal pole and loop that 6-foot body up over my baffle and clean out my box, and it’s most heartbreaking. So when this starts happening, you got to mount them on a taller pole and higher so that a big snake can’t loop up over them.
Margaret: Right? Oh my goodness.
Julie: I’m kind of living in a lab here, Margaret, where I’ve been watching these processes for so long, and I’ve seen all different kinds of predation, and it’s constantly changing. Guess what my most feared predator is now?
Margaret: I don’t know.
Julie: It’s extremely cute and nocturnal. There’s a hint.
Margaret: Extremely cute and nocturnal? Cute. That’s a funny word. Because I mean, nocturnal here is opossums, and raccoons come out.
Julie: Yeah. Yeah. I don’t think they’re cute at all.
Margaret: No, that’s why I didn’t know who you thought was cute [laughter].
Julie: No, my worst predator is the flying squirrel.
Margaret: I was going to say the flying squirrel is really, really, really cute, but really, really, really small. That’s fascinating.
Julie: Yep. They can get in the hole and they can fly to the box.
Margaret: Wow.
Julie: So baffles mean nothing to the flying squirrel. So what I’ve had to do is relocate all my boxes to farther than a squirrel can glide from the nearest tree. And that is tricky. Yes, I have 80 acres, but finding a spot where there isn’t a tree, where a squirrel can’t launch onto it, is becoming a challenge.
Margaret: That’s really interesting. See, I’ve never thought of them as predatory for something like eggs or nestlings. You know what I mean? It just didn’t compute in my head that that’s what they’d be out doing at night [laughter]. I’ve seen them and they’re hilarious; oh my God, they’re so beautiful. Those eyes and the little ears and-
Julie: I know. I have one sampling Zick Dough [homemade bird food] in a little feeder by my studio window, and I about died of the cute when I saw him, but they are very rapacious. They’re blood-thirsty like chipmunks.
Margaret: I didn’t know that.
Julie: And they’re major nest predators. And what a lot of people don’t know is that in some parts of the country that is the single most abundant mammal.
Margaret: See, I didn’t know any of that. And again, I’ve had them here all the time. I just didn’t know that was their deal, because I’ve never had an encounter like you’re describing with them that I’ve observed. So other than predators—let’s forget about them for a minute.
Julie: It’s all predators for me [laughter].
Margaret: I know [laughter]. Everybody’s got to eat, Julie. Everybody’s got to eat. So: Cavity nesters. ,I said at the beginning that usually the tree swallows win out and get the boxes, and the bluebirds don’t here where I live, and that’s fine with me. If you put up a nest box, maybe you don’t get a pair of bluebirds, but who else might you get—do you ever get other birds in any of your nest boxes?
Julie: Oh, yes. Yeah.
Margaret: So tell us about some of them, because I think it’s wonderful whoever decides to use them.
Julie: Sure, sure. Within reason, there are some who I don’t permit [laughter], but here, the gamut of birds that I can get is Eastern bluebird, tufted titmouse, tree swallow, white-breasted nuthatch (the holy grail), and house wren, which I don’t love, and house sparrow, which I absolutely do not permit to nest in the boxes.
Margaret: Right, right, right. Yeah. I am going to confess: You just said house wren, which you’re not thrilled by. I keep one box, a very old little funny handmade box, right on the side of my house, literally attached to the siding not far from my door, the main door that I come and go in and out of. And it’s always a house sparrow [wren]. And really, it’s a funny thing. It’s just like it’s the worst place to have the box because he or she’s just screaming at me all the time and I’m irritating him or her all the time. You know what I mean? And it’s just this hilarious conversation every year. But that’s kind of what charms me because they’re so funny and so small and so bossy. They’re so bossy.
Julie: Yeah. You’re talking about a house wren now.
Margaret: I’m sorry, I didn’t mean house sparrow. I meant house wren [laughter].
Julie: Because you said they’re great little birds, very spunky. And they only have one Achilles’ heel. And that is when the male is prospecting for a nest site, he goes to every cavity in his territory, which can be rather large, and he will pierce and throw out the eggs of any other bird nesting in that area.
Margaret: Oh, O.K.
Julie: I think that’s great that you have your house wren box right on your house and hopefully a good distance away from the tree swallow nest.
Margaret: Yes. Hundreds and hundreds and hundreds and hundreds of… Yeah, 2 acres away. Yes.
Julie: So showing what a great eggslayer he is part of his breeding thing for the female. “Look, I eliminated the competition for you.” [Laughter.] So I actually had a house wren come through my place, come up my driveway and go out my meadow throwing the eggs out of every box that was there.
Margaret: Oh my goodness.
Julie: And I heard him singing in the morning and I thought, oh my Lord. And sure enough, that’s how he spent the day, and everybody had to relay, and then he moved on.
Margaret: Demonic. Oh, it was terrible. I’ll never look at one the same again.
Julie: Vilified.
Margaret: Julie, I’m always glad to talk to you, and thanks for the advice about bluebirds and the proper accommodations, should we be so lucky as to host a pair in the spring ahead in the breeding season ahead.
Julie: I always love talking with you, Margaret. Have a great day.
(Illustrations and photos by Julie Zickefoose; used with permission.)
enter to win a copy of ‘the bluebird effect’
I’LL SEND A SIGNED COPY of Julie Zickefoose’s “The Bluebird Effect: Uncommon Bonds with Common Birds” to one lucky reader. All you have to do to enter is answer this question in the comments box below:
Do you have any nest boxes for any birds in your garden? Who?
No answer, or feeling shy? Just say something like “count me in” and I will, but a reply is even better. I’ll pick a random winner after entries close at midnight Tuesday, March 4, 2024. Good luck to all.
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prefer the podcast version of the show?
MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 15th year in March 2024. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the Feb. 24, 2025 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify (and browse my archive of podcasts here).
