Despite its reluctance to fly, the roadrunner is not in danger and Richard Collins tells us how the grounded bird keeps thriving.

Will Trump’s equivalent of the Great Wall of China affect wildlife along the US-Mexican border?

Nobody is sure but human migrants are unlikely to be its only victims. More than 1,100km of fencing was erected during George W Bush’s reign. Trump’s 10m-high wall is intended to close off the remaining sections of the 3,200km-long frontier.

Animals approaching it may find their access denied amid blue flashing lights of 4x4s, clattering helicopters, rifle-touting border-guards and ‘minutemen’ members of the local Neighbourhood Watch. Sensitive ecosystems could also be damaged.

In 1950s Australia, land of the ‘rabbit-proof fence’, almost 5,000km of continuous fencing protected sheep from marauding dingoes. It also helped kangaroos, the dingo’s traditional prey. Their numbers mushroomed, as did their impact on the grass the sheep needed.

Nor do barriers have to be fences. Antelope Valley, at the western tip of the Mojave Desert, is named after the pronghorns which once grazed there. The pronghorn isn’t an antelope, but was mistaken for one. When a railway was built through the valley in the 1880s, the pronghorns were afraid to cross the tracks and about 30,000 died of starvation.

Excessive hunting, drought, and climate change were also factors, but the railway is blamed for the catastrophe. Only small numbers of pronghorn are found there now.

The mountain lions of California’s Santa Anna Mountains, trapped between motorways, are becoming inbred because they can’t access mating partners from elsewhere. Closer to home, tunnels are provided so Irish badgers can cross motorways safely.

Burrowing species readily enter tunnels but few others will. Underground passages might allow some small creatures traverse the Mexican frontier but they won’t help larger animals. Birds will be least affected by the wall, but that famous cartoon character, the roadrunner, doesn’t like barriers.

About 50cm long from bill to tail, the largest of the American cuckoos lives in desert and scrubby areas of Mexico and the southern United States.

The state bird of New Mexico, it’s capable of catching and killing venomous snakes, including small rattlers, by banging their heads against rocks. A ground dweller, it can sprint at 30kph. Up to 42kph has been recorded. But roadrunners are very poor flyers, reluctant to take wing. They have already been affected by the existing fences, it has been claimed. This is not, however, a threatened or vulnerable species.

The bighorn sheep, whose ancestors came across the Bering Strait about 750,000 years ago, will find that they can no longer cross the Mexican border. Cats and bears will face a similar restriction.

The secretive dwarf leopard, the ocelot, once lived in Arizona Louisiana and Arkansas. Fewer than 100 remain in southern Texas. Contact with the larger populations of Central America will be lost if Trump’s monstrosity is built.

The bobcat, a species of lynx twinned with the coyote in American myth, will also be restricted but there are at least 1m of them in the US and Mexico. The mountain lion, a secretive and solitary cat, travels extensively searching for prey and mates. It needs to move freely to and from Central America.

The jaguar, largest of the New World cats, was hunted to extinction in the gun-obsessed ‘land of the free’, the last one being shot in 1963. Recent sightings and camera-trap photographs suggest jaguars from Mexico are returning to some of their former haunts. Trump, no doubt, will soon put a stop to that. Black bears, reintroduced to Texas, may need to meet their cousins south of the border if they are to maintain genetic diversity.

But the effects of barriers aren’t always negative. During the ‘iron curtain’ era, plants and animals flourished undisturbed between two huge lines of fences dividing Europe. Could Trump be persuaded to build not one wall but two, a few hundred metres apart, creating a unique nature reserve 3,000km long between them?


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