Idaho works to identify pronghorn migration patterns

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Idaho works to identify pronghorn migration patterns

Idaho works to identify pronghorn migration patterns. (Idaho Department of Fish and Game)
Idaho works to identify pronghorn migration patterns. (Idaho Department of Fish and Game)

Published in, August 25, 2019

  by COLIN TIERNAN (Associated Press) 

BELLEVUE, Idaho (AP) – The helicopter banked left and tracked its  quarry over the field for about 10 seconds before the net gun went off  with a distant pop. The chopper touched down abruptly and two men,  helmeted and clad in orange, leaped out and bolted toward the captured  pronghorn.

It was an unwelcome surprise for an animal that had  been calmly grazing in a green-gold field, back dropped by the  Sawtooths. But the Idaho Fish and Game Magic Valley Regional Office had  good reasons Aug. 8 for descending on pronghorn from the sky and  capturing them with nets fired from guns. Compared to other big game  species, like elk and mule deer, pronghorn in Idaho are understudied.

“We  know they summer in one place and winter in another,” Magic Valley  Region Fish and Game Wildlife Manager Mike McDonald said. “What we don’t  know is how they get there.”

Fitting  a pronghorn with a collar allows Fish and Game to track the animal’s  movements throughout the day and throughout the year. Now, with new data  on pronghorn travel habits, Fish and Game will be better able to manage  the species and protect important habitat.

Fish  and Game hasn’t captured and collared pronghorn much in the past. This  summer’s two-day effort, which resulted in 24 newly collared animals in  Camas and Blaine counties will dramatically increase the agency’s  knowledge of local pronghorn.

“This is part of putting together a database,” McDonald said.

When  big game animals cross busy roads, crashes that endanger both animal  and driver are inevitable. If Fish and Game can learn where pronghorn  cross, the agency can devise strategies to make crossings safer.

U.S.  Highway 20 is a hot spot for pronghorn crossings. The animals need to  cross, but they could benefit from crossing structures, such as an  overpass.

When it comes to wildlife crossings, pronghorn are a bit picky.

“They’ve got to go over,” McDonald said. “They don’t like underpasses.”

Overpasses  and underpasses are expensive – they can cost millions of dollars – so  it’s important to pinpoint areas of high crossing density before  breaking ground.

Today, Fish and Game is essentially working with  anecdotal data when it comes to pronghorn. Pronghorn summering in Blaine  and Camas counties might be wintering in the King Hill area in Elmore  County or north of Gooding. They might be spending the cold months near  Eden or Hazelton in Jerome County. Many pronghorn winter at Mountain  Home, but Fish and Game isn’t sure where those animals are summering.

Figuring  out pronghorn road crossing preferences is important, but there are  also more general reasons for studying the species better.

“This  collar data is going to allow us better insight into the daily  activities of these animals across the whole year,” Idaho Fish and Game  Regional Wildlife Biologist Sierra Robatcek said.

Fish and Game is  making a significant investment in order to beef up its pronghorn  knowledge. Between helicopter costs and a roughly $600 collar, it costs  about $1,000 to capture a pronghorn.

That cost could easily be  worthwhile if it helps Fish and Game conserve pronghorn while  south-central Idaho’s landscape changes. The Magic Valley could be  seeing new solar, wind or hydroelectric projects in the coming years.

“That’s great, but it’s also concerning from a migration standpoint,” Robatcek said.

Big  projects can have big impacts on pronghorn. If Fish and Game can  identify critical habitat, the agency can work to ensure that pronghorn  don’t run out of the land they need for survival.

“It will help us try to guide development in these areas that are really critical to pronghorn,” Robatcek said.

“They’re touchy”

Working  with pronghorn isn’t like working with mule deer or elk. For one,  pronghorn have different biology – they’re more closely related to  giraffes than mule deer or elk.

From a capture perspective, pronghorn are a bit more fragile. They’re also incredibly fast, capable of running 60 mph.

“Capture  is kind of bittersweet,” Robatcek said. “It’s really fun to be  interacting with animals that closely – that’s why I became a biologist.  But there’s also this risk to the animal and to the people.”

There  are a number of precautions Fish and Game has to take when capturing  pronghorn. They can’t chase the animals for more than three minutes,  because pronghorn can literally run themselves to death. Lactic acid  build up can cause muscle death, which can kill the animal in a slow,  agonizing way.

It’s also important to process a pronghorn quickly.  After the helicopter swoops low over a pronghorn and the gunner pulls  the trigger on the net gun, it’s critical for the two-person processing  crew move fast.

“The younger you are, the more fun it is,” Idaho Fish and Game Senior Wildlife Technician Clint Rasmussen said with a grin.

The  crew extracts the pronghorn from the net and pins the animal safely to  the ground. A blindfold relaxes the animal a bit, but a pronghorn will  still grunt and moan loudly while being handled. The crew processing the  pronghorn pay careful attention to the animal to ensure that it doesn’t  overheat. If at any point the pronghorn appears too stressed, the  processors let the animal go.

“Our priority is keeping the animal alive,” Robatcek said. “There’s no point in putting a collar on a dead animal.”

While  they collar the pronghorn, the crew also takes a fecal sample (if  possible), tags the ear and extracts blood. Then the technician will  carefully unwrap their legs from the pronghorn and let it run away, no  worse for wear but with a new, high-tech necklace. The whole process  only takes a few minutes.

Idaho Fish and Game’s Ryan Walrath and  Jon Prokott processed a pronghorn at the Heart Rock Ranch near Bellevue  Aug. 8. Both Walrath and Prokott come with a wealth of experience,  Robatcek said.

“Those two are fantastic, they’re some our  quickest,” she said. “They’re light, agile, speedy guys. They care  tremendously about the animal.”

Walrath said that the animal he and Prokott processed Aug. 8. was in good shape.

“She  was good,” the Magic Valley Region Fish and Game Senior Wildlife  Technician said. “She was strong, good, healthy, a fighter.”

Working with pronghorn isn’t all helicopter chases, firing net guns and processing the animal. It’s also a lot of waiting.

“I’ve  had to shave twice,” Heart Rock Ranch Owner Harry Hagey said with a  grin while waiting for the helicopter crew to arrive. “(The pronghorn)  have dropped dead from old age.”

But the early mornings and long  waits, Fish and Game biologists look forward to the days they get to fly  and work with animals in a hands-on way.

Robatcek said she thinks  pronghorn are a bit of a forgotten animal in Idaho. Hunters can talk  about goats, sheep, elk, mule deer and moose for hours without even  mentioning pronghorn. She said that this new data will be a great  benefit for Idaho pronghorn, and she hopes people take time to notice  the animals.

“Pronghorn, a lot of people don’t think they taste  very good, or they live in this habitat that’s often driven by on your  way to something prettier,” Robatcek said. “I think they don’t get the  attention they deserve.”