• Blog
  • August 12th, 2018


By Joel M. Vance

Non-migratory wildlife being, well, non-migratory is subject to the same problems as people when the neighborhood goes to ruin. It’s difficult if not impossible to pick up and move to a better ‘hood.

Ducks, geese, other peripatetic types, can light a shuck for new territory—but how can you fill a wildlife vacuum with animals that don’t want to move?

Fortunately wildlife biologists have invented an array of methods to get wildlife from here to there and the result is a series of remarkable comebacks of endangered or threatened wildlife species by trap-and-transplant. They’ve been trapped by an array of schemes, some right out of a Three Stooges comedy.

It all started with a device designed for a migratory species. Sir Peter Scott, son of the famed explorer Robert Falcon Scott (who froze to death during an Antarctic expedition in 1912) devised a rocket net that could be fired over waterfowl.

The birds then could be banded, aged, sexed and otherwise studied. Rocket nets worked when they worked…but often they misfired or tried for a space launch. Scott wrote about his adventures and misadventures with the rocket net and a pair of innovative wildlifers at Missouri’s Swan Lake National Wildlife Refuge, manager Herb Dill and staff member Howard Thornsberry, read what he wrote.

Thornsberry, a mechanical marvel, devised a “cannon” which more resembled a mortar. It fired a dependable missile at a dependable trajectory. The “missile” was a weight attached to the leading edge of a net. A pair of mortars, fired in unison, would launch the net over baited birds.

Since Dill and Thornsberry began using their net in 1950 to capture Canada geese for tagging and study, the cannon net has become a staple in the wildlifer’s arsenal, used to capture both deer and turkeys. Sandhill cranes and tundra swans also have fallen for bait and been netted.

Box traps are as old as the country and still are in use—in fact, box traps were the trap of choice for Dill and Thornsberry before the advent of the cannon net. But the drawback for flock creatures was that box traps don’t catch enough animals. Instead of one goose or turkey at a time, the cannon net can catch 25-50.

Trapping gathers animals for transplant to suitable, but uninhabited habitat also allows researchers to equip the critters with tracking devices so they can be studied. Sometimes the motive is to thin a population of animals that have become nuisances.

Urban wildlife problems are a relatively new phenomenon and, faced with increasing incidence of people vs. critter, biologists have two choices: either kill the offending animals or relocate them. Relocation is the usual (and more desirable) choice.

What do you do when a 1,600-pound bull moose invades your city? Anchorage, Alaska, has faced this situation. Other than hunters, the only predators on moose are wolves and vehicles (about 160 collisions a year in the Anchorage area). Wolves by their nature are rural residents, not city dwellers…which leaves the Anchorage moose with only one predator, the SUV, and as powerfully-built as four-wheelers are they don’t stand up well to a collision with a moose.

Alaska sees a thousand or more car-moose encounters each year and the moose toll is more than 500. Several people also die. So, while back country moose populations in Alaska have declined in recent years, the city herd has increased dramatically…and with increasing friction between the animals and those to whom a moose is an accident waiting to happen.

Gray wolf restoration in Yellowstone is a fact. Controversial or not the reintroduction there produced a rare alliance against the project between the Sierra Club and ranchers—Sierra arguing that the introduction of trapped and transplanted Canadian wolves would dilute the gene pool of any indigenous wolves remaining, and ranchers simply not wanting large predators. But the project went ahead, beginning in 1994 after a number of court challenges.

There even was controversy over how to catch wolves: trap, live-snare, tranquilizer darts from helicopters, or nets fired from helicopters. The biologists decided to dart wolves in Alberta and supplement with wolves neck-snared by trappers (the snare has a stop to prevent strangulation). After all the court battles, biologists captured 33 wolves in the first go-around, one of which died.

Two decades later wolves still are at the center of a controversy over whether they should be managed as trophy animals or “delisted” in much of the state, to be taken at any time in any numbers. Regardless, the capture methods and the reintroduction both were highly successful.

Some years ago a wolf release in Minnesota involved transmittered animals. When one signal became stationary, wildlife officers investigated and found that a farmer had shot the wolf, discovered the transmitter collar and then panicked. Not realizing the transmitter continued to broadcast, he buried the wolf in his manure pile. He was fined but he got to keep his manure pile.

In Wyoming the Rocky Mountain Elk Foundation contributed nearly $400,000 through 2003 to wildlife management, which includes elk transplants. Counting cooperative contributions, the total is more than $1.5 million.

Wyoming Game and Fish used cannon nets for sage grouse. Researchers studying West Nile virus in sage grouse in Powder River Basin night netted sage grouse with a spotlight and a big dip net. Wyoming also has used just about every capture method for a variety of wildlife. Including pronghorn antelope caught for relocations to other states where large numbers (more than 30) are needed are driven into a big corral trap by helicopter. Other big game animals are generally darted, but researchers used clover traps for some things like deer and elk and have used drop traps baited with apple pulp for capturing large numbers of bighorn sheep. Ferrets are live trapped with a special long, narrow trap that looks like the usual Havahart or similar live traps.

Grizzly bear relocations (usually related to human/grizzly or livestock/grizzly conflicts) within the Yellowstone Ecosystem are via culvert traps or snares and then immobilization via dart gun or jab stick.

As retired Montana game warden Louis Kis found out in 1987, a culvert trap can work both ways. He was relocating a grizzly bear in the Bob Marshall Wilderness. Photographer Richard Smith was along to record the release. The bear, instead of heading for the woods, turned on the trap and dragged it, and Kis who was standing on it, out of a truck bed.

The bear grabbed Kis by the leg and Kis grabbed his .357 pistol and emptied it, somehow managing to avoid shooting himself in the leg. He killed the bear, thankful to be alive, although his leg was broken. Smith, whose first instinct was to help, realized a motor-driven camera wasn’t much of a weapon against a ticked-off grizzly bear and did what photographers always do—he kept shooting until he ran out of film. Kiss got mauled, but Smith made considerable money off the photos of the attack. Usually the trappers win, but not always.

Some years back a Canadian moose tagging team was working from a helicopter. The procedure was to herd the moose into a lake deep enough that the animal had to swim. Then the chopper could hover above the swimming moose while a biologist leaned out and clipped an ear tag to it.

The idea worked well…until the moose reached a submerged island and lurched out of the water, dumping the helicopter on its side. Fortunately no one was injured, but the pilot and biologist had to swim to shore and hike for help.

Among the more unusual trap ideas is a mailbox, used to snare ruffed grouse. Male grouse use a “drumming log” to advertise their virility. The male finds a downed tree, preferably with a bit of overhead cover to discourage hungry horned owls, and “drums,” a wing beat that sounds like a distant tractor starting up.

Mating males are competitive. Grouse trappers placed a common rural mailbox with a mirror inside on or near the log. The grouse would glance inside the box, see what appeared to be a competing male, and charge in to do battle, tripping a door behind it. The device worked on male birds, but a population of males won’t proliferate. So the trappers devised a miniature version of the corral, used by Westerners for decades to trap wild horses. Grouse prefer to walk unless they must fly, so the trappers placed 50-foot, 18-inch-high chicken wire fences or “leads” which led to a wire cage on either end.

A wandering grouse would reach the fence and, like someone looking for a gate, amble along it into the cage from which it couldn’t escape. A similar technique is used for geese during their molt period or before goslings can fly. They’re herded into a corral, chased down, captured and tagged or transplanted. It’s a raucous scene, often involving bloodletting—that of the biologists who are flogged and clawed by angry geese (wrestling an eight-pound Canada goose has many similarities to wrestling a bobcat).

Earlier researchers relied on tagging (a leg band or a visible colored plastic tag on the wing), hoping that observers would report sightings or dead animals. These days radio telemetry is the key method. Transmitters allow biologists to track the activities of everything from timber wolves to bobwhite quail.

Wildlife capture inevitably runs afoul of animal rights activists who focus on the stress and occasional mortality associated with capture. An elk that wandered into Missouri some years ago was dart tranquilized because of local fears about Bangs disease. The elk died…and proved negative for Bangs. But wildlife management is predicated on the health of the population, not the individual. While some individuals may die during a trap-and-transplant project, the ultimate judgment rests on the establishment of a viable population—and there have been far more successes than failures.

In fact, some of the successes have become problems. Giant Canada geese, which once were thought to be extinct, now are thriving to the point of being pest animals, especially in urban areas where they can’t be hunted. They munch on gardens and foul golf courses with droppings. And a 15-pound gander protecting a nest can be a ferocious adversary.

River otters (captured with leg hold traps which are, according to animal rightists, cruel) have been transported hundreds of miles, released…and have established healthy populations in 18 states. Lee Roy Sevin in Louisiana used leg hold traps to capture river otters which he sold to wildlife agencies around the country. Missouri’s river otter restoration has been so successful that the animals have become a localized nuisance.

Since an initial release of 20 otters in 1981, the Missouri otter population has reached at least 10,000 animals and they are being accused of depredation on fish hatcheries and the smallmouth bass population in small streams. A couple of otters loose in fish hatchery pools can do major damage and otters in steam headwaters will eat fish as long as the fish are available

“If an otter wants to catch a fish in open water the fish doesn’t stand a chance,” said the late Glenn Chambers, retired wildlife biologist for the Missouri Conservation Department, and “father” to captive river otters for 30 years. Missouri’s otters are a remarkable wildlife restoration success, despite the problems. More than 5,000 otters have been trapped for their fur, yet the population remains healthy—a population that did not exist 20 years and more ago.

So it is with the mammal version of catch-and-release: today’s triumph may be tomorrow’s problem…but that’s better than having nothing left to create the problem.

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