In general, it’s surprising how little conservationists know about why large animals choose their migration routes. The motivations for moving are obvious and include things like food, water and a safe place to raise the young. But how herds or animals learn their routes is a major debate. Evolution plays a certain role. There are signs of genetic predisposition in birds, for example, which can fuss about in their cages as the seasons change, even though they have always lived in captivity, and in insects like the monarch butterfly, which takes every year the same way to Mexico. . But in mammals, this kind of genetic programming is harder to see. Their movements seem more strongly influenced by the peculiarities of their environment and the behaviors they have learned from the generation that preceded them. A young mule deer, for example, will learn the path taken by its mother down to the nearest meter.
Recent research has supported the idea that hoofed animals like mule deer develop these migratory routes in part by riding the green wave. By maximizing their daily calories, they learn to evolve with the seasons. Attempts to restock the American West with bighorn sheep offered a natural experiment to the idea, as the animals transported to do the restocking had no particular mental map of their new habitat. Initially, they preferred to stay put, found a team of researchers from Wyoming. But gradually, the spring shoots proved irresistible and began to attract animals to explore new territories. Over time, they became better surfers, and these migratory routes were then passed on to their young.
The results of the mule deer study indicate that once the animals have learned an ideal path, it can be difficult for them to shake. And therefore, any sort of obstruction presents a problem, as researchers have found in previous studies. “Animals that migrate the longest distances and are the best surfers consistently have the highest body fat,” Aikens says. “These are the ones most likely to survive the harsh winter.” The research team then plans to capture some of the animals involved in the study and measure their fat thickness using an ultrasound device.
The results contain lessons on the lasting effects of development on other migratory species. This includes caribou, for example, which Hebblewhite studies in Canada’s Far North. Although they are a little better at changing their routes, he says, they still face declining populations as huge mining and fossil fuel operations create a thicket of obstacles in their path.
For Hebblewhite, the Wyoming findings underscore the importance of considering migration patterns when considering development, not just for oil and gas, but also for clean energy installations like solar farms. Although these routes can sometimes be inconvenient for developers, all is not lost, he points out. The majority of deer preferred to cross the two gas sites that appear in the study, but migration route maps show plenty of empty land where no deer roam. A developer could sink wells there and drill laterally to reach the natural gas under the flyways, he says: “This article points out that you could have avoided their routes. That doesn’t mean you have to quit everything.
As more GPS data becomes available, animals’ surf routes are already increasingly factored into development decisions, Hebblewhite adds. State and local governments are often receptive, he says, due to the importance of hunting to local residents and a growing understanding of the interconnectedness of ecosystems — that if you care about Yellowstone’s natural wonders , you may also need to worry about what happens. to a mule deer in the sagebrush scrub plains hundreds of miles away. The challenge, Aikens adds, is getting that kind of detailed data for more animals and in other parts of the landscape where people may want to build. “It’s surprising how little information is available in many places,” she says. “It’s something that there is an active effort to change.”