Koala Windows May 2026

Enter the engineers. Traditional wildlife crossings—overpasses planted with native shrubs—were too expensive for this narrow rail corridor. Tunnels failed because koalas rarely enter dark, enclosed spaces on the ground. But a chance conversation between Lin and a structural engineer, Tomás Reyes, led to a radical idea. Reyes was designing a noise barrier for a new housing estate. "What if," he asked, "we make the barrier rough, planted, and vertical? A fake tree that's actually a real habitat?"

They installed five prototypes. Within a week, a female koala named "Bumpy" (for the scar on her nose) was photographed climbing one, pausing at a ledge, and using it to cross over the tracks without ever touching the ground. The panel had a small, circular opening near the top—a "window" through which a koala could observe the other side before committing. Reyes, an amateur photographer, captured Bumpy peering through that hole, her furry face framed like a portrait. The image went viral locally. "Koala Window" stuck.

This is the story of how a problem became a solution, and how a solution changed the way a country thought about its roads. koala windows

Her report was clear: "Koalas perceive vertical structures as trees. To a koala, a steel post is a eucalyptus. The solution is not to stop koalas from climbing—it is to give them a tree worth climbing."

Reyes replied: "So we didn't build a crossing. We built a lesson." Enter the engineers

It started in the early 2010s on the eastern slopes of the Great Dividing Range, where the Brisbane-Sydney rail line cuts through a remnant patch of eucalyptus forest. Koalas in this region—already stressed by habitat fragmentation and chlamydia—faced a new, silent predator: the 8:15 AM express train. Collisions were rising. A koala, when startled on the ground, doesn't run. It climbs. And the nearest vertical structure was often a steel rail signal post.

But the heart of the story remains a single email. After the bushfire, Dr. Lin wrote to Reyes: "Bumpy made it. She used the window three times in one night. Her joey was with her. She showed him how." But a chance conversation between Lin and a

The results were astonishing. In a two-year trial along a 3-kilometer stretch of rail, koala mortality dropped by 91%. Gliders, possums, and even a goanna were recorded using the windows. The structures required no lighting, no moving parts, no electricity. They worked in drought and flood.