‘Ghosts’ hard to find because of drought
Early this summer, as the West-wide drought dug its claws deeper into western Colorado, biologists knew all was not well with the pronghorns living in the desert south of Grand Junction.
One year earlier, researchers and biologists from Colorado Parks and Wildlife radio-collared 19 pronghorn in the small herd wandering between Grand Junction and Delta.
Ten of the collared animals were part of the resident herd, while the other nine were among 24 pronghorn the state recently had moved into western Colorado from southeast Colorado.
It was thought the newly arrived pronghorns would augment the existing herd, which in recent years had been shrinking for various little-understood reasons.
Biologists would use the radio-collared animals to gather information about the habitat utilized by the pronghorn and whether the animals were successfully raising young.
With their deer-like body and distinctive white-and-tan camouflage markings, pronghorn blend so well with their surroundings they sometimes are called “prairie ghosts.”
In recent years, however, the “ghosts” are even harder to find because of the widespread drought.
Pronghorn are more susceptible to drought than other large ungulates, and it’s not only in Colorado that pronghorn numbers have been impacted by the drought.
Texas biologists say prolonged drought is one reason the state’s pronghorn herd has shrunk from about 17,000 in the mid-1980s to a 30-year low of 3,745 animals last year.
In Wyoming, where pronghorn have been a common sight, “We are seeing very poor habitat conditions and very low numbers of pronghorn antelope during our initial classifications and observations,” Lander Region wildlife supervisor Jason Hunter said last August.
“In some areas, the fawns we are seeing seem very small for this time of year, and some adults appear to be in poor condition as well,” Hunter said. “As for the habitat, we are seeing some sagebrush plants losing their leaves. The plants are not dead, but they are in poor condition due to lack of water.”
The plan to monitor the pronghorn between Delta and Grand Junction ran into a major problem: The difficulty of locating the animals.
“It was pretty grim in that part of the world,” said Northwest Region senior terrestrial biologist Brad Petch of Colorado Parks and Wildlife, speaking about drought conditions in the desert.
“Pronghorn in early summer were widely scattered, both the resident antelope and the transplanted ones,” Petch said. “It’s interesting that even the recent transplants weren’t clustered up, and this can only be attributed to the need to get to a water source.”
Animals searching for water set off in smaller family groups rather the larger, easier to find herds. Adults and newly born young are forced to travel farther for water, competing with other wildlife and livestock for water holes.
The loss of late-spring and summer plants not only robbed young pronghorn of critical forage, but it may have increased predation.
A study by the Kansas Department of Wildlife, Parks and Tourism said coyotes are the main predator of pronghorn, and drought-reduced plant cover may make young fawns easier to find by predators.
Furbearer biologist Matt Peek of Kansas’ Wildlife, Parks and Tourism said pronghorn are like deer in that when the adults go feed, they often leave their young animals alone and bedded down.
“For 10 days to two weeks, (the fawns) are pretty vulnerable. Then after that, they can run,” said Peek in an article online at Outdoors Kansas.net.
Colorado’s Petch said biologists still are weighing all of the factors affecting the local pronghorn herd.
He said more information will be available later this winter after biologists finish their annual aerial census counts.