DOW Moose Transplant Update
The Colorado Division of Wildlife (DOW) has made the first step toward establishing a moose herd on the Grand Mesa in western Colorado. A cow and two bull moose were released on the Mesa after being transported from the upper Rio Grande area near Creede.
Sadly, Tuesday’s release was marred by the still-unexplained deaths of three animals, and biologists immediately suspended further capture efforts until wildlife veterinarians can determine what caused the deaths.
"We're saddened by the loss of the three moose," said Jeff Madison, senior terrestrial biologist for the DOW’s northwest region. "We spend our lives caring for these animals and we hate to see anything like this happen."
The idea of establishing a moose herd on the Grand Mesa has been around for years, but gained momentum when the idea was formally presented to the DOW by two area residents in 2001.
The DOW held a number of public meetings last year, including several with Grand Mesa landowners, to gather input, answer questions, and address initial concerns. A habitat assessment by the DOW and the U.S. Forest Service showed sufficient willow forage on the Grand Mesa to support a moose population. Additional public meetings were held following the habitat findings, and public sentiment was strongly in favor of proceeding with introduction efforts.
"Moose are one of the biggest draws when it comes to watchable wildlife," said Ron Velarde, northwest regional manager for the DOW. "When you see a moose it is not uncommon to see a crowd of people, too."
Colorado is currently home to two other healthy moose populations. The DOW introduced the first significant breeding population in North Park in the late 1970s. A second successful introduction near Creede was conducted in the early 1990s.
"We chose to take animals from the Creede herd to start the Grand Mesa herd so that we could fulfill a commitment we made to the public and public land managers years ago," said Tom Spezze, DOW southwest regional manager.
The DOW set the initial moose population objective in the Rio Grande National Forest at 300-400. Current population estimates are above the initial objectives, and hunting alone was not sufficient to keep the numbers closer to the desired herd size.
"We realize these animals are coveted by locals for viewing opportunities, just as they will be coveted by the people on the Grand Mesa as the new herd grows," Spezze said.
The three moose released this week were fitted with radio transmitters to allow DOW biologists a chance to track their movements.
Meanwhile, a preliminary review of the three fatalities and the capture procedures identified no single cause as likely being responsible for the three moose mortalities. Deep snow may have added to the stress on the animals during helicopter pursuit.
The first moose that died took longer than usual to become entangled in the capture net because of deep snow, and likely became overexerted. A second moose died shortly after being captured by the helicopter net gun crew, and no cause for its death was apparent in the field.
Those two deaths resulted in DOW biologists and veterinarians making the decision to switch from net gunning to chemical capture. Two successful captures raised hopes that the worst part of the day was behind the capture crew, but the unexplained loss of a third animal, a calf, led DOW personnel on the scene to immediately suspend the entire operation.
"The capture methods we were using have proven quite safe and successful for moose in the past. We are hoping that necropsy and laboratory results can provide a little more information, though we may never know all of the circumstances that contributed to each case" Madison said.
Pathologists currently are performing further tests in an attempt to determine cause of death in all three cases. Test results will take approximately seven to 10 days.
“Based on what we’ve seen thus far in the field and at necropsy, it seems most likely that the combination of running in deep snow and perhaps other underlying physiological factors led to the deaths of the three moose lost during this capture operation,” said Dr. Lisa Wolfe, field veterinarian for DOW. “We hope to learn as much as we can from these unfortunate cases to help us prevent similar problems in the future.”
Mortality is not unexpected in wildlife capture operations, but rates this high are very unusual. The DOW does everything possible to minimize problems, however animal deaths can occur from stress, exhaustion, disease or parasitism, equipment problems, tranquilizers, or any combination of other factors.
"Obviously, before we attempt to move any more moose from the Creede area, we want to do everything possible to make sure we don’t have problems like this again,” Velarde added. “We're upset by the loss of these great animals and saddened that it has dampened the excitement over the release of moose on the Grand Mesa.”