Richard Wildlife Collins: Minimise Would On Impact Animal Traffic Crossings

Thu, 19 Jan, 2023 - 12:05

Richard Collins

When Francis preached love to the birds They listened, fluttered, throttled up Into the blue like a flock of words — Seamus Heaney

If we could ‘talk sense’ into animals, they might cope better with life’s ‘slings and arrows’. Alas, they can’t understand us, nor are we much better at fathoming their thoughts. Oh for an animal version of the Rosetta Stone!

A mountain lion known as P-22, in the Griffith Park area near downtown Los Angeles. Picture: US National Park Service

Mountain-lion, P-22, tagged in 2012 by the Fish and Wildlife Service, warmed to people. Photographed under the famous sign on Mount Lee, he became ‘The Hollywood Cat’. Beloved by residents of Griffith County Los Angeles, whose gardens he visited, P22 became legendary. Alas, recaptured last month, with multiple injuries inflicted by road vehicles, he had to be ‘put down’.

The P-22 mural by artist Corie Mattie, dedicated to the memory of P-22, the celebrated mountain lion who lived in the city and was recently euthanised amid worsening health and injuries likely caused by a car. P-22 became the face of a campaign to build a wildlife crossing over a Los Angeles-area freeway to give big cats, coyotes, deer and other wildlife a safe path to the nearby Santa Monica Mountains, where they have room to roam. Picture: AP Photo/Damian Dovarganes

Responding to the carnage inflicted on the likes of P-22, bridges and underpasses were constructed along highways in California, so that deer wild boar and mountain lions could cross safely. Animals were expected to use them readily but a problem arose; ‘neophobia’, fear of the new, discourage many from doing so.

They fail to understand that it’s safe to use the new facilities. As the Captain said to Cool Hand Luke: "What we've got here is a failure to communicate". But the problem isn’t universal.

Animals cross fearlessly at some locations, whereas at others they don’t. But what exactly is spooking them? Researchers at UCLA have tried to answer this question. They focused on the behaviour of elk and white-tailed deer. Much hunted in gun-obsessed America, these two mammals exhibit hair-trigger hyper-vigilance.

Colorado Highway 9 Wildlife Crossing Project Thanks to Colorado's first-of-its-kind wildlife overpass and underpass system, animlas are able to safely cross Highway 9. Researchers have recorded thousands of successful movements of animals including mule deer and elk using the crossing structures. Picture: Colorado Parks and Wildlife

The team analysed footage from almost 600 cameras nationwide, creating ‘activity budgets’ and measuring changes in the time spent foraging versus vigilant behaviour and flight.

The research results appear in a paper just published. The authors note: "Overall, both white-tailed deer and elk responded to vehicle passage with a decrease in time allocated to foraging and an increase in both vigilance and flight behaviour."

But fear of vehicles varied. Those animals most sensitive to passing traffic were the least likely ones to use bridges or tunnels, whereas individuals relatively unfazed by vehicles did so readily. But, surprisingly, steady streams of vehicles presented less of a problem than did the occasional passing car.

"When more vehicles pass, they produce a louder sound that is detectable at a greater distance. Thus animals might not be startled by an oncoming vehicle and have time to respond to it."

The Wallis Annenberg Wildlife Crossing which is under construction in California

This particular finding won’t surprise bird-watchers in North County Dublin. The flight path to the old north-south runway at Dublin Airport crosses the Broadmeadow Estuary, winter home to flocks of waterfowl and shore-birds.

The runway is no longer used but, in its heyday, noisy aircraft flew low over the estuary. Although there was a constant stream of air traffic during busy periods, the birds took little notice of aircraft. They had become acclimatised to the noise. Familiarity breeds contempt!

Wallis Annenberg Wildlife Crossing: Construction has officially begun on the Annenberg Wildlife Crossing which will be the world’s largest animal crossing. When completed, the crossing will stretch across ten lanes of the 101 Freeway and help local wildlife cross safely between critical biological hotspots throughout the region

What do the researchers recommend? In an animal equivalent of the ‘Safe Cross Code’, they want the impact of roads to be minimised’ near wildlife corridors. Tunnel walls should be sound-proofed, lights blocked and the visibility of traffic reduced.