I don’t remember the first time I saw an eastern bluebird, but I do remember the first time I saw one at a nest box.
I was birding at a nature preserve and saw a male bluebird flutter to the top of a nest box on a pole in a meadow, and then go inside. It was a sunny, spring day and the blueness of the bird was so striking amid its all green-brown surroundings. i didn’t know at the time that the blue was not pigment, but the play of light on feather structure.
The box also made a strong impression. What a simply perfect arrangement. A little wooden enclosure to provide a home for bluebirds and allow us to easily watch them. The birds are content and we’re happy with this artificial-but-so-natural cavity.
I wasn’t aware of how the boxes had come to be, and that there was more to them than just another way, like bird feeders, to put birds in our line of sight.
I did know right then that I wanted my own nest box to attract my own bluebirds. I didn’t have a place for one at the moment, but not only did I resolve to have a nest box when I did have a place, but I thought that being able to put up a nest box was a good reason to get a place.
Several years later I had a place; a backyard surrounded by large trees. By this time I knew the conservation concern that had led to bluebird nest boxes with their carefully sized entry hole.
I bought a bluebird box and nailed it to a post of a wooden fence in the backyard in the spring. I’m not sure if bluebirds visited the box that first season or not. I do recall, however, that bluebirds did not nest in the box the first year I saw them in the yard, and I thought that, whether a pair of birds nested or not, getting to see them examine the box was wonderful in itself.
Bluebirds eventually did nest in the box, which also attracted other birds, some of whom, such as downy woodpeckers, used it as a winter roost.
At some point I learned that nailing a box to a fence post made any eggs or birds in the nest easy pickings for predators, and I moved the box to a pole placed in the middle of the yard with a baffle below it to foil raccoons and snakes. In the roughly 20 years since, bluebirds have nested in the box every year, often producing two broods. I often wonder if the bluebirds nesting in a particular year have used the box before, or if they themselves were born in the box.

I have bird feeders in the yard as well as a nest box, and I began to keep notes of the species that visited the yard, sometimes counting how many species dropped in on a particular day. I live in Connecticut, and I had the typical crowd at the sunflower, thistle and suet feeders: titmice, chickadees, goldfinches, cardinals, woodpeckers, nuthatches, juncos, sparrows, house finches, jays, etc. Rather than just list the birds, I began to take a few notes on the bluebirds’ doings:

April 11—bluebirds building nest, taking mealworms as soon as offered (I had bought live mealworms by mail for the bluebirds and stored them in the refrigerator)
May 15—for several days, bluebirds have been taking worms straight to nest box … don’t know when fledge will come, so reluctant to look in box (you don’t want to open the box and cause the nestlings to fledge early.)
May 18—bluebirds seem to be trying to lure nestlings out of box by calling from perches
May 25—nestling poised at nesthole at 6 a.m.
May 26—birds have fledged
June 9—three fledglings in the yard. male feeding them. seemed to be teasing them, flying from spot to spot, with them following, and gaping as they perch next to him
July 2—second brood of bluebirds hatched in second nestbox (I must have switched out the boxes, probably just to encourage a second brood and give the birds a clean start.)
July 10—saw a bluebird fledge today, 46 days after the first brood fledged… saw second nestling fledge, also pooped upon leaving box
July 30—three baby bluebirds on the deck with mom, still being fed and not taking worms themselves
August 1—three BB babies coming to mealworms … seems like two males and a female (bluebirds are thrushes and the young are spotted on the breast like juvenile robins)

And so on. I have notes over the years about chasing the neighbor’s cat out of the yard, and doing battle with house sparrows, or HOSP. House sparrows, like starlings, were introduced in North America from England, and win the competition with bluebirds for nesting cavities. A nest box with an entry hole one-and-a-half inches in diameter thwarts starlings, but HOSP can slip through it into the box. HOSP will kill bluebirds in the box. One of the ways used to keep HOSP out of a box is to string fishing line down from the roof of the box on either side of the nest hole. Because the roof juts out from the front of the nest box, the fishing line will hang free beyond the entry hole. For some reason, it can deter HOSP, who don’t seem to want to fly between the lines to enter the box. It is not foolproof, however, and HOSP have entered my box after a while. The bluebirds recognize HOSP as a threat and will do their best to fight them off, but they are mostly unsuccessful. There are few things that cause me more consternation than seeing HOSP in the yard. I actually have a sense of dread when I spot one. Fortunately, it’s a rare occurrence. As an invasive species, HOSP are not protected by law and may be “harvested.” I will take the fifth if asked whether I have ever harvested one during a bluebird-HOSP skirmish in the yard. I will admit to being more invested in this strife between tiny bird-brained combatants than I am about many battles, violent or otherwise, among humankind. Indeed, there have been a few occasions where I went in late to work, or took the day off, because a battle was looming between bluebirds and HOSP and I was determined that evil would not prevail.
My current nest box of choice is made from a length of plastic pipe about four inches in diameter, which is considered to be less attractive to HOSP than a larger, square wooden box. This is only the second season I am using the cylindrical “box,” but I have yet to see a HOSP at it. I also don’t put out any food at my feeders that HOSP eat.

Another “problem bird” is the house wren. It will sometimes fill a nest box with twigs to keep other birds from nesting, and I’ve opened my nest box to see it full of twigs. They will also peck holes in bluebird eggs and remove them from the box. I have found punctured bluebird egg shells on my deck. House wrens are a protected native species, and if they nest in the box they should not be disturbed. They usually do not use boxes out in the open, and are not a regular problem in my yard.

A few years ago I bought a camera with a telephoto lens and have taken pictures of the bluebirds in the yard. I have also discovered that a weatherproof GoPro camera, which can be operated remotely, is a great way to take close photos and videos of the bluebirds.
Of course, I also watch the bluebirds through binoculars and a spotting scope. As seen through a binocular, the variety of wriggling insects the bluebirds bring to the nest box for their young is remarkable. One time I saw a male deliver a large dragonfly to the mouth of a nestling at the entrance of the box. The nestling could not swallow such a large mouthful, at least not as it was positioned in its beak, and the parent returned to pull the dragonfly out and reinsert it.

Bluebirds do visit the yard year round. They will visit the suet feeder in winter, sometimes pecking at the suet themselves, or flying to the ground below it when a woodpecker is feeding, and picking up the suet crumbs as they fall.
I was in the yard one cold winter day at dusk and saw four bluebirds land next to each other on the wooden fence. They fluffed up their feathers for a while and then, one by one, the puffballs entered the nest box for the night. I checked the yard the next evening at the same time. After a wait of several minutes, the four bluebirds returned and went through the same ritual.
I am an older male with diminished hearing, and birding by ear is largely impossible for me. I can be watching a songbird singing from a perch a short distance away and not hear a thing. Fortunately, the soft warbling of a bluebird is low-pitched enough for me, and I have no trouble hearing their liquid song in the yard.
This winter I put a roost box up in place of a nest box. It’s a larger box with the entrance hole near the bottom rather than the top, and the interior has perches. When I heard bluebirds in the yard, I replaced the roost box with last year’s PVC pipe bluebird box and a pair of bluebirds claimed it immediately, clinging to the entry hole and poking their heads in and out, telling each other that this is the place. There is now still a week left in winter, and the female is already bringing nest material into the box. I’m betting on an early brood.