RENO, Nev. (AP) — Mike Piercy was readying his Truckee, Calif., home for winter one afternoon when he tripped over a strange-looking device on the ground.
It was a calling card from deer No. 79897.
With mule deer numbers dwindling, biologists have been tracking deer and studying their annual Reno-Truckee migration to identify critical habitat that must be protected to maintain the herd.
Deer No. 79897 was tranquilized by biologists on Reno’s Peavine Peak in January 2010 and fitted with a satellite collar. The doe sported the device throughout the winter and in the spring as it wandered to its summer digs in the Truckee area.
The next fall, the collar accompanied the doe as it scampered down the Truckee River Canyon to the Reno area to weather winter’s snows, then again as the deer crossed the state line back into California as the seasons turned. Ultimately, the collar dropped off as it was designed to do.
Piercy picked it up, recognizing the device as a tracking collar for wildlife. As requested by a stamped notice on the collar, he dropped by the Nevada Department of Wildlife and asked if officials wanted it back.
They did. Data later downloaded from the collar — which had malfunctioned so it couldn’t be located by the department — was incorporated into a study conducted by biologists from Nevada and California. The scientists, who had collared 25 does, were monitoring the movements of deer that migrate twice each year through the Truckee River Canyon.
Among the conclusions of the $170,000 study: These mule deer make their Truckee-Reno migration at about the same time each year. Their departure dates are only days apart and they travel very close to the same route every time, the Reno Gazette-Journal reported (http://on.rgj.com/M4btGF ).
“They’ve got their path dialed in,” said Mike Cox, big game biologist for the Nevada Wildlife Department. “The take-home message is that these mule deer have an innate and learned behavior to use the same route time after time.”
Why? The answer is relatively simple, Cox said. They do it because it works.
The deer take roughly the same route because it’s easiest, it takes less energy, and because they know where there is forage to feed upon, Cox said. Taking the same path may also help reduce the risk of being ambushed by a predator.
The deer studied are among a population of roughly 1,000 animals that belong to the Truckee-Verdi herd, a sub-herd of the larger Loyalton-Truckee herd that regularly migrates between the two states in the Sierra.
The migratory nature of the animals made it important that Nevada and California cooperate on research vital to the deer herd’s future, said Sara Holm, associate wildlife biologist for the California Department of Fish and Game.
“They really are an interstate herd and they can’t be managed separately,” Holm said.
Learning more about deer migration habits is more than a matter of academic interest, Cox and Holm agreed. The Truckee-Verdi herd is now only a quarter to a third the size it was 50 years ago.
The reasons are many but are predominantly connected to loss of habitat, summer range in California, winter range in Nevada and the migration corridors that connect both places.
Land is being lost to wildfire, which chews through vegetation needed for forage and cover. It’s also being covered by houses, a problem that is expected to accelerate when the economy improves.
When that happens, biologists hope the information gathered in the migration study will result in smart decisions.
“Things will get back into the swing — land will be bulldozed and habitat destroyed,” Cox said. “We will be asked where do we need to have habitat protected or restored. Now we have a pretty good idea.”
Among the study’s surprises for Holm was how some deer stay put in relatively small areas during the summer months, in some cases venturing within only a few square miles. She expected them to wander around a lot more.
“They’re definitely creatures of habit,” Holm said. “These guys kind of have these small pockets that they use and that makes these pockets all the more important.”
Preserving land used for migration is a key goal when it comes to protecting a mule deer population that is diminishing across the West, agreed Miles Moretti, president of the Utah-based Mule Deer Foundation. The group helped support the Nevada-California research.
“When they migrate, they’re pretty specific. That inflexibility is in part why they are in trouble,” Moretti said. “We’ve got to get smarter about protecting these migration corridors.”
Grateful that Piercy returned the satellite collar he recovered outside his home, Cox has shared some of the data collected during the study with the Truckee resident, including details on the travels of deer No. 79897.
“Not only was the route very similar between years and seasons, but (data indicated) how synchronized her May migrations were between the two years; only one or two days different, and that is without a watch,” Cox wrote in an email to Piercy.
“I thought it pretty interesting that they have such a good internal clock,” Piercy said, adding that he suspects the deer that dropped its collar near his front steps has probably been munching on his flowers this summer.
Cox said the deer migration, while smaller today, remains a marvel.
“It’s pretty neat to think these deer are continuing something that they’ve been doing for 1,000 years,” he said.
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Information from: Reno Gazette-Journal, http://www.rgj.com
