I was walking alongside Bristol on the edge of a tiny airfield on Haida Gwaii, forty miles off the coast of British Columbia.
He was eighty two. Just out of the hospital. Wearing Adidas cross-trainers with neon yellow soles that skimmed the grass as he shuffled forward, eyes locked on the sea.
He didn’t want to wait inside the airport for our flight to Vancouver. He wanted fresh air. The smell of the tide going out. The smell of life.
At one point, he stopped at a tall fence, grabbed it with one hand, and shook it gently.
“This never used to be here,” he said.“Oh yeah?”“I used to walk the entire way around this field waiting for flights when I was younger.”
He paused, assessing the fence. “Not quite hoppable, eh?”
I smiled at the idea of this eighty-year-old man considering hopping a fence—though knowing Bristol, he probably would have tried it forty years ago. Maybe even yesterday, if he hadn’t spent the last two days in the hospital.
When our ship arrived a few days earlier, Bristol, the ship’s naturalist, had seemed confused, tired. While the other guests explored the island, we brought him to the hospital. Dehydration. Serious at his age. By the time he was released, the ship had already sailed.
I had hired Bristol a year earlier after securing the ship’s route from Seattle to Alaska, now including the exploration of Haida Gwaii. The first thing my boss told me?
“Call Bristol Foster.”
Bristol is a biologist. A naturalist. A man who studied island species across British Columbia and noticed a pattern:
On islands, big animals tend to get smaller.Small animals tend to get bigger.
Not randomly, but because the island demands it.
Food is limited. Space is constrained. Conditions are different. Predators change.
So species adapt.
It’s adaptation at its most pragmatic. The island decides what works.
“It’s sort of a P.S. to Darwin,” Bristol said with a wink.
The theory became known as Foster’s Rule, one of the five rules of evolutionary biology, though Bristol never loved the name.
“Who the heck is Foster? Who cares? As long as it serves the people, that’s all that matters. Island rule is fine.”
As we walked the airfield, he pointed things out with quiet joy.
A bird burst from a bush.“Pigeon falcon,” he said in a flash. “Or Merlin. I like that name better. Sounds more magical, right?”
What I saw as bushes became rose hips.What I saw as white berries became snowberries.A burnt stump became, in his words, “a wondrous stump!”
That’s when I realized:Bristol wasn’t just stretching his legs.
He was being who he was, despite the hospital stay, the fence, the flight home waiting.
He had adapted.
The Island Rule Isn’t About Biology
I didn’t fully understand it then, but I do now.
Foster’s Rule isn’t just about animals on islands.It’s about what any environment asks of us.
Islands don’t care who you used to be or who you want to be.They care about what works here.
And life is full of islands.
A new job.A marriage.Parenthood.A loss.
When I became Director of Expedition Development—responsible for millions in revenue, hundreds of staff decisions, and trips people had saved for their entire lives to take—I had my own island moment.
I panicked.I doubted myself.I wondered if I belonged.
The things that had once made me feel big—confidence, certainty, momentum—suddenly felt oversized. Unsustainable.
And the things I had ignored—asking questions, slowing down, listening—had to grow.
That’s Foster’s Rule in action. And it happened when I got married, became a father, lost a job, broke my knee, you name it.
If you’re standing on a new island right now, here are the questions I wish I’d asked sooner:
* What parts of me are too big for this place? Old identities. Old coping mechanisms. Old measures of success.
* What parts of me need to grow? Curiosity. Patience. Humility. Care. Courage.
* What am I trying to force that this island is asking me to release?
When it came to moving on or pivoting from things I loved most deeply, I used to see it as quitting, or acknowledging defeat. But adaptation is intelligence.
My time with Bristol ended as we reached the edge of the airfield, I checked my watch.
We had an hour before the flight when checking in fifteen minutes early would have been enough.
“Looks like we have some time to kill,” I said.
Bristol stopped, turned toward the breeze.
“I think time is too valuable to kill,” he said. “Maybe we say… we have extra time to explore.”
So we did.
What island are you on right now? And what is it quietly asking you to become?
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