Monday, November 23, 2009

For deer collisions--wolf pee or wishful thinking?

Collisions between deer and vehicles cost the US $1.4 billion a year in property damage and injuries, not to mention the 200 deaths of drivers.  Source

So, what to do about this?   On The Lede, many readers advocate more hunting or re-introduction of wolves, to reduce deer populations.

But the solution getting the most traction in Minnesota?  Spray wolf pee about.  Really.

I'm not a fan of pee against pests, because it avoids the real cause--what's attracting pests in the first place.  And I don't believe the testimonials you see about predator pee on websites--testimonials are no substitute for real evidence.   I don't really believe there are fox farms or wolf farms out there, milking the predators and bottling the real stuff. 

Joel Berger said: "As a biologist conducting studies of prey reactions to re-introduced predators, we exposed naive and savvy moose from Wyoming and Alaska to wolf urine and grizzly bear scats. The result... is that moose learn to avoid predators if re-enforcement occurs. Without re-enforcement, these animals (like deer) soon figure out what is dangerous and what is not. Hence, there may be a short-term effect."

Here, reinforcement means that if bears or wolves are present in the area, moose learn to be fearful of the predator smell.  If not present, the moose wouldn't have any reason to fear the scent.

Arguments against wolf pee
  • Predators like wolves are absent in most of the US--so according to Berger, deer won't fear wolf pee.
  • Even if they do fear wolf pee, it doesn't follow they won't cross roads that have been sprayed with urine.  They may be driven to cross by hunger or that cute doe on the other side.
  • Will the wolf pee last long enough, once sprayed?
  • Will deer still care when the entire countryside is sprayed with wolf pee?
  • Can the wolf farms be ramped up fast enough to save the day with tanker loads of wolf urine?
  • Will people object to having wolf pee sprayed everywhere?  (OK, maybe they will invent a synthetic urine--but that doesn't change things much.)
  • And what about the porcupines?  They're attracted to urine--they crave the salt.  Maybe we'll just substitute porky collisions for deer collisions.  Or other unintended consequences??
In short, the urine debate smells like "better living through chemistry." We'll just spray some perfume around, and the problem will go away.  No one will have to give up any convenience, and politicians won't have to make any hard decisions--like reducing the deer herd.    Spraying contractors and wolf farms, along with their lobbies, will get rich.  Sound familiar?

Deer whistles for cars are also ineffective.  Same story as predator pee.  More

What does work

When deer block a beam of light at a deer crossing near the highway, they trigger a warning for motorists.  If you can't control the deer, maybe you can control the drivers.  It's called "animal detection."

"Only fencing and animal-detection systems like the one being tested in Minnesota have had much success..., said Marcel Huijser, a research ecologist...."

Huijser, who studied more than 40 methods of reducing accidents involving deer, moose and elk, said fencing off areas of road where animal-related crashes frequently occur has been shown to reduce those accidents by 87 percent.

Special overpasses and underpasses can be built to allow animals to cross the roads, and although fence construction can be costly, society can benefit by the number of lives saved, he said."

"Some drivers attach special whistles to the fronts of their cars to warn deer to get out of their way. But the whistles are of little use and one frequency was actually more likely to cause accidents, according to a recent study by University of Georgia researchers.

Experts say the best ways to avoid deer on roads are slowing down at night and paying attention in areas where deer are commonly found."   From Joe Kafka, Associated Press

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