A bird with a call like my phone’s alarm squawks once in a tree near my bedroom window, forcing my eyes open. It’s impossible to tell the hour from the charcoal sky outside; if my phone said it was midday, I would believe it.

The truth is almost as distressing. The bird went off some time before my actual alarm, but not early enough to make going back to sleep worthwhile, unless I first reset the alarm to something more civilised, which I then do, before lying awake until it goes off 20 minutes later.

By quarter past seven I am in my office shed, staring at a blank page. At 7.30 the squirrel – my enemy – pauses on his journey along the top of the garden wall to stare down at me through the little rectangular window above my computer screen.

“You,” I say. I stare. He stares back, not moving, or blinking.

I used to think these standoffs were an attempt on his part at intimidation, but I now realise they’re intended as a distraction: he doesn’t want me to see what’s going on outside the window behind me.

My enemy the squirrel is actually a composite character made up of several squirrels working in concert. When I turn around, I see another squirrel hanging upside down from a bird feeder, and another one keeping lookout.

“Look at this,” my wife says at lunchtime, holding out pieces of broken bird feeder. “He pulled it off its hook and let it smash to the ground. Now there’s seed everywhere.”

I don’t say what I’m thinking, which is: I know; I watched the whole thing. I sympathise, but it’s not my fight.

“Amazing,” I say, finally.

“This feeder was meant to be squirrel-proof,” she says.

“You can’t win,” I say.

“Yes, I can,” she says. “I actually enjoy having an adversary.”

“I don’t think that’s how you pronounce adversary,” I say, apportioning generous and even weight to each syllable.

“That’s American,” she says.

“Your way is not among the acceptable options,” I say.

“Adversary,” my wife says, again pronouncing it so it rhymes with bursary.

“Are you an Edwardian?” I say. “Just say ‘enemy’. It’s shorter.”

“Bastard,” she says, meaning, I think, the squirrel. But I’m not sure.

Later that afternoon she comes out to my office holding a length of strong chain.

“How do I cut this?” she says. I take hold of a link, appraising its thickness.

“You might need a hacksaw,” I say. “Why?”

“It’s for the squirrel,” she says. “He’s getting at my fat balls.”

“Sorry?” I say.

“He worked out how to unclip the lid and he took two and ran off,” she says. “When I tied it shut, he chewed through the string and took two more.”

“Clever,” I say. “Your red squirrel would never think of that.”

“Because he’d be lying on the ground, dead from some imported virus.”

“A lack of initiative is what it is,” I say. “You have to want it bad enough.” I realise I have more or less handed over my animosity toward the squirrel, whom I now see as a plucky immigrant thriving against the odds in a hostile environment.

The next morning I spend 15 minutes watching the squirrel attack the fat ball feeder, which now hangs from a shiny chain, its lid wired shut. He’s having no luck.

“Keep probing,” I say. “Look for the weak points.”

An hour later, I go back into the house. My wife is standing by the window, smiling.

“He can’t do it, can he?” she says.

“Give it time,” I say. “He’s working it out.”

“My fat balls are for native species,” she says. “Like my lovely finches.”

“This morning I saw all the finches get chased away by pigeons and supermarket birds,” I say.

“What’s a supermarket bird?” she says.

“The black ones that live there,” I say. “They run around the car park and hide under trolleys, eating crisps.”

My wife stares out the window, arms folded. The sun appears briefly, glinting off the wet bricks, before the dark clouds close in again. A rising breeze stirs the bare branches.

“Do you mean starlings?” she says.

“What am I, a taxonomist?”