Thousands of pronghorn killed by harsh winter

15/06/2011 22:55:14

1000 pronghorn killed on a single railway line
June 2011. "The past winter ranked as one of the most severe on record and included an incredible nine feet of snow in the Glasgow area," said FWP wildlife biologist Kelvin Johnson. "Severe winter conditions started in mid-November and extended through April in many areas. Pronghorn antelope were one of the hardest-hit species in the region. Under normal conditions, many pronghorn migrate southwards to survive when the snow gets too deep. However due to a wide variety of factors over the winter of 2010 - 2011, many of them could not keep moving south to get out of the harsh weather and they simply died."

Disaster - for hunters? Tough.
While this is a terrible event, the pronghorn herds will recover - There are estimated to be more than 300,000 in Montana alone. However the major slant of the media coverage in North America was that it was bad news for hunters as they would not be allowed to shoot so many pronghorn in 2011.  There was barely a shred of pity in the press coverage for the thousands of pronghorn, and no doubt many thousands of other animals too, that have succumbed to the harsh winter. But the poor old hunters won't be able to kill quite as many as they qould like. Doesn't anyone appreciate them for what they are rather than just as a target?

An ongoing research study of pronghorn habitat selection and migration showed that last winter started a full month earlier than normal. Concurrently, many animals started to move south then to minimize exposure to extreme conditions.

Winter range was covered by snow
"Traditional winter range located along the Milk River Valley was completely covered by snow, and very little forage was available," Johnson said. "Antelope began relying on haystacks but they suffered high rates of mortality there, in part because they're not adapted to digest that type of food. At least 200 pronghorn carcasses were found at one particular haystack alone."

Roads and railways used for migration - 1000 killed on 1 rail line
Johnson noted that the migrating pronghorn used county roads, highways and railroad tracks as travel corridors. Survey flights flown this spring confirmed that approximately 1,000 pronghorns were killed by trains in one region alone. The animals often got crowded together on and along the tracks because they were unable to travel elsewhere in the deeply drifted snow.

2-3000 pronghorn trapped 
Large herds of pronghorns also trekked across the frozen surface of Fort Peck Reservoir, but wildlife biologist Ashley Beyer said 2,500 to 3,000 of the animals are now stranded on the reservoir's remote southern shoreline from the mouth of the Musselshell River east to Snow Creek. These animals are unable to get back to their traditional summering grounds now that the ice has melted.

Charles M. Russell National Wildlife Refuge
"Hundreds of antelope have also been observed stranded on the south side of the Charles M. Russell National Wildlife Refuge near UL Bend during the past few weeks, and they're trying to migrate across the reservoir," added University of Calgary doctorial candidate Andrew Jakes, one of the leaders of the international study.

"Collaborators were able to document interesting behaviour in these groups, and in the observed cases groups swam approximately one-third of the way across but then turned back around with only the lead does successfully making it to the north banks of the reservoir."

Hundreds of carcasses
"As the snow has melted, the carcasses of hundreds of pronghorn antelope that had been trying to winter along their traditional winter range along the Milk River Valley have appeared," Johnson added. "Most of the local winter range that typically works for them was not available this year, and it is evident that the vast majority of animals that tried to stick it out died. It appears that if the antelope didn't migrate far enough south to the Missouri River Breaks or across Fort Peck Reservoir, they didn't make it."

"Not all is lost, however," Johnson said. "In 2010, we had some of the best habitat conditions ever recorded in the summer and fall, and our antelope went into winter in the best body conditions possible. For the pronghorn that survived the past winter and soon will be dropping their fawns, there should be plenty of good habitat to live in again this summer. The record snowfall and persistent spring rains have made forage abundant almost everywhere."