Corridor Ecology: Carnivore Migration Patterns

In the Age of Man many large-carnivore migration patterns have been disrupted. Corridor Ecology allows us to research humankind’s impact on these innate animal behaviors.

| July 2014

  • Wild Lynx in it's Natural Habitat
    “Although the young lynx didn’t know it, in addition to a bulky collar he’d acquired a name: BC03M02. Wildlife managers and scientist had moved him to the United States for a lynx reintroduction program.”
    Photo by Fotolia/Marcel Schauer
  • Corridor Map
    Map of the Carnivore Way, showing large-carnivore distribution for six species: grizzly bear, wolf, wolverine, lynx, cougar and jaguar.
    Illustration by Curtis Edson; courtesy Island Press
  • The Carnivore Way Book Cover
    In “The Carnivore Way,” author Cristina Eisenberg follows the footsteps of six large carnivores on a 7,500-mile wildlife corridor from Alaska to Mexico along the Rocky Mountains.
    Cover courtesy Island Press

  • Wild Lynx in it's Natural Habitat
  • Corridor Map
  • The Carnivore Way Book Cover

What would it be like to live in a world with no predators roaming our landscapes? In The Carnivore Way, (Island Press, 2014), author Cristina Eisenberg argues compellingly for the necessity of top predators in large, undisturbed landscapes, and how a continental-long corridor – a “Carnivore Way” – provides the room they need to roam. This excerpt examines the current migration patterns of these large carnivores and the impact that industrialized North America has had on them.

In early 2003, a two-year-old male lynx (Lynx canadensis) was cruising through his territory near Kamloops, British Columbia, searching for prey. As he maneuvered through the forest, padding easily in deep snow, he picked up the scent of food. He lowered his nose, took a step, and paused. All at once, what should have been just another in a lifetime of simple steps proved ill-fated. He found himself caught. No matter what he did, he couldn’t free his paw from the hold of a trap. Soon a human came along and jabbed something sharp in his rump, which rendered him unable to move. When he came back to his senses, his life had changed in surprising ways.

Although the young lynx didn’t know it, in addition to a bulky collar he’d acquired a name: BC03M02. Wildlife managers and scientist had moved him to the United States for a lynx reintroduction program. Eventually he was released into southern Colorado’s high country. It was much drier there than in his northern Rocky Mountain home where he was born, and there weren’t as many snowshoe hares (Lepus americanus), his favorite prey. But he found a willing, fecund mate and enough to eat. Life was good; in two years he sired three litters of kittens. And then one day in late 2006, something in his brain, some inchoate longing, some homing instinct, made him feel like roaming. At first he simply traveled from one snowshoe hare stronghold to another, finding food when he needed it. After a while he started ranging farther, and eventually just kept going. He ended up crossing landscapes unlike any he’d experienced before: the Wyoming Red Desert, followed by the Greater Yellowstone Ecosystem.

Colorado Parks and Wildlife (CPW) biologists determined that over the next several months the lynx covered 2,000 miles. His last recorded collar signal before the battery gave out occurred in late April 2007. Eventually BC03M02 found his way remarkably close to where he was born, near Banff National Park, Alberta. And there his life ended, in another trapline—a lethal one set to legally harvest fur-bearing mammals. Superbly healthy at the time of his death, wellfed, with a luxuriant coat of fur, he set a world record for the greatest known distance traveled by one of his kind. Despite his tragic end, BC03M02 proved that even in our fractured world, it’s possible for a carnivore to roam widely. But ultimately, the media hoopla about how far he’d traveled belied the tragedy of his death.

In recent years, lynx from the CPW reintroduction project also have dispersed south, into New Mexico’s mountains. Researchers didn’t anticipate these dispersals, which involved crossing interstate highways, traversing areas of high human use, and dodging death in myriad ways. En route, these dispersers had to find snowshoe hares to eat—not always an easy task.

Other species besides lynx have an innate need to wander. These instinctive journeys involve both migration, defined as seasonal, cyclical movements from one region to another and back for breeding and feeding purposes, and also dispersal, the process animals use to leave their natal range and spread permanently from one place to another. Many species, such as pronghorn (Antilocapra americana) and elk (Cervus elaphus), migrate as part of their annual life cycle. Fewer species disperse. Wolves (Canis lupus), wolverines (Gulo gulo), cougars (Puma concolor), jaguars (Panthera onca), lynx, and grizzy bears (Ursus arctos) have natural histories that often include long dispersals (although grizzly bears don’t disperse as far as some of these other carnivore species).

10/11/2015 12:06:14 PM

Good article. Lets stop using the word "harvest" about animals. We "harvest" wheat, we kill animals. Donato

10/9/2015 1:05:55 PM

Gee, isn't it fun using big word that you can't pronounce?

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