For weeks now, we've had to explain the phenomenon to visitors. It never takes them long to ask.

For weeks now, we've had to explain the phenomenon to visitors. It never takes them long to ask.

It reminds me of when my older daughter was 3 years old and a climber. Turn your back for two seconds and she'd go from the kitchen chair to the table to the counter to the cupboards.

Pulling her down grew tiresome, so I took to turning the chairs upside-down on the kitchen floor, which worked until someone unfamiliar with toddlers came by. My sister, for instance, would come in the back door and pick up the chairs all pretty much in one motion, while I followed behind her like the second voice of a perpetual canon, putting the chairs down again.

That's how it is now. Just a few weeks ago, dinner guests hadn't been on the premises five minutes before the questions started. "I suppose there's a reason for the newspapers," they said, and my husband and I looked at each other.

We had grown accustomed to having two of our living room windows covered with newsprint, and it hadn't occurred to us to take it down before the friends arrived. Not that it mattered. Even if we had remembered to remove it, we'd still have been questioned about the windows.

"What's that tapping sound?" our friends would have asked.

We explained, awkwardly. There's this bird. The bird wants in. Or maybe it sees its reflection in the window and believes another bird wants out. Or maybe it's demented in a birdy kind of way, and it's compelled by its delusions to spend all daylight hours flying from window to window, hopping up and down on the thin edge of the screen and flapping its wings until it loses its grip and drops several feet.

Then it pulls itself together and rises up again, perching, flapping, falling with a "thonk;" perching, flapping, falling, thonk. The windows and the screens are a mess, on both the upper and lower stories.

I run on a treadmill, and for weeks my daily workout has been attended by our neurotic little friend, who flaps first at the south window and then at the west one while I run. Later, it turns up at the windows of my office, where I swear it fixes me with one beady little eye while it taps and thonks, taps and thonks.

Clearly, this bird has a message it is desperate to deliver. If it could, it would carry a sign in its mouth saying "Let me in!" or "I have no idea why I'm doing this" or, ominously, "Flee! Flee while you still can!"

My husband thinks the bird's mate failed to return after winter, and now the bird has concluded she must be inside our house, eating chilled birdseed and watching DirecTV while he's stuck outside. I'm more inclined to believe the bird sees himself in the glass and is besotted by his own dazzling reflection. Or maybe, as I say, he's just addled.

You'll notice I started referring to the bird as an it and promptly slipped into calling him he. This is what happens when an annoying stranger from another species forces himself into the family circle: After a while, you begin to bond with the intruder, like Stockholm syndrome only weirder.

The bird may be a she, but I doubt it. Females are way too busy in spring building nests, laying eggs, raising chicks and fetching food to waste hours arguing with window glass.

Not that I don't empathize with this bird. I empathize a lot; I'm getting nothing done, thanks to listening to the now-familiar tapping and thonking going on outside. (The newspaper keeps him away from those living room windows, but he just moves on to others, like the Mad Hatter and the March Hare changing seats at the tea party.)

It reminds me of Laura Ingalls Wilder's description of the 1870s grasshopper plague -- in fact they were Rocky Mountain locusts, but that hardly matters here -- in On the Banks of Plum Creek. That swarm was 1,800 miles long and 110 miles wide. Our swarm is one bird long and one bird wide, but believe me, I'm feeling just as wild-eyed.

"We can't help you!" I tell the bird, not unkindly. And, "She's not in here!" and "What the heck is your emergency?"

The bird never answers, or even pauses in its frenzy. He's doomed to flutter frantically at the window until we invite him in or he collapses from exhaustion. I've decided to name him Sisyphus.

Write to Margo Bartlett at margo.bartlett@gmail.com.