50-Year Dream: Bridge Becomes Wildlife Corridor Over M1

Bob Crombie was a young ranger in the mid-1970s when he realized wildlife couldn't survive if they couldn't move freely across the landscape. Now 88, he's watching his half-century dream become reality above one of Australia's busiest highways.

Cawleys Bridge, a forgotten utility structure near Sydney's Royal National Park, is being retrofitted into Australia's first repurposed wildlife corridor. The transformation allows animals to safely cross the M1 Princes Motorway, which carries 40,000 vehicles daily and has acted as an impenetrable barrier between fragmented bushland for decades.

Crombie first proposed the idea in 1974 when government departments were just beginning to understand how essential movement was for native species survival. Royal National Park looks like one large 14,000-hectare reserve, but it's actually several isolated patches separated by roads and development.

The bridge was always there, quietly carrying utilities overhead while traffic roared below. Crombie saw its potential on old maps and thought, "Hallelujah, we've got a wildlife corridor."

Now ecologist Kylie Madden is bringing that vision to life. Logs recovered from recent land clearing nearby have been repurposed to create natural pathways across the bridge deck. Soil and 700 native plants will soon mimic the forest floor, while elevated ropes will let gliders and possums travel above ground.

Every design detail encourages animals to cross as if they're moving through continuous bush. Ground cover will protect smaller creatures from predators, and the structure accommodates everyone from butterflies to swamp wallabies.

The Ripple Effect

This project represents more than one crossing. It's a blueprint for reconnecting fragmented habitats across Australia without building expensive new infrastructure.

Transport for NSW director Matthew Burns said the project gave bridge carpenters unique experience working from "a koala's point of view." Cameras are already installed to monitor which species return and how they use the crossing over the coming years.

Butterflies have already been spotted crossing through the unfinished structure. The team can't wait to capture the first wombat, possum, or koala making the journey safely overhead.

For Crombie, seeing construction crews install the final waterproofing and planting before the mid-March completion date feels surreal. He didn't think he'd live to see it happen.

When animals start moving freely between habitats again, they'll be walking across a bridge between the past and future, proving that patient vision and creative thinking can heal landscapes we once thought were broken forever.