Deer Are Big Business With No Big Predators

By Bob Engel
Marlboro College Professor Emeritus of Biology and Environmental Science

The New England deer herd is large.  What’s large? Healthy Native American forests in the lawsuit I mentioned last month had one deer/ square mile.  What’s the Vermont herd?  After a mild 2015 winter, one estimate put the herd at 145,000 deer.  Vermont is comprised of 9,623 square miles.  Therefore, we have 15 deer per square mile (more, probably, because deer don’t do well in cities, lakes, or interstates).  That’s almost twice the density of the deer herd (8/sq. mile) that brought the law suit in the Wisconsin National Forests.  The scientists there showed a real problem, and we have one here.

So why are there so many deer in Vermont?  Easy, the State and we make money off of them, a lot of money. According to the 2011 publication of "Hunting in America: An Economic Force for Conservation", Vermont made $192 million dollars from everything from licenses to lunches; from guns to granola; from gas sales to truck sales.  Almost 2000 jobs were supported in the process, and $14 million were paid in State and local taxes.  Bambi is big business.

But doesn’t Lyme disease cost money to treat? And if deer are even just half of the Lyme problem, how does the hunting income compare to treatment costs for the disease?

In 2015, the treatment costs for all Lyme in the U.S. was $1.3 billion dollars, or about $3000 per patient.  Vermont reported 599 Lyme patients in 2014.  So 599 times $3000 per patient means that someone forks out $1.8 million to treat Lyme per year.  And this is conservative, is it not?

These were 599 confirmed and probable Lyme cases; how many more fly under the medical radar for at least a year? Further, what are the added costs of Lyme morbidity when the disease escapes treatment and becomes chronic?

In any event, my back-of-the-envelope calculations show that Vermont (the State and anyone else who sees deer hunter dollars) gets about 100 times more from hunting than it spends in the direct costs of treating Lyme.  Further, if deer and their ticks are only a fraction of the problem, the ratio of monetary benefit to cost gets even larger.  Thus, there is little economic incentive to cut down on the deer density.  People want their deer more than they fear the ticks.  And between us chickens, a lot of people want their deer to come easily — open the door and have it jump in — so we’re just going to have to fence our gardens.

One final point?  Currently, we humans are the primary predators of our deer.  The occasional killing by gray wolf-gene-carrying coyotes in deep snow or the odd spring fawn by black bears probably occurs.  But without either wolves or mountain lions here, it’s up to us (only in the fall) and particularly harsh winters to cull the herd. 

The field of ecology has not yet settled the argument about whether predators control their prey.  Several long-term studies have show that ungulate prey are more likely controlled by the availability of food than by their predators.  Here in Vermont we humans have created ideal habitat for deer — a lot of edge with abundant, succulent growth resulting.  If we had wolves and mountain lions in the State, we might be able to actually ask the ecological question.  In the meantime it’s hunters with rifles, muskets, and bows that kill deer.  What might be the outcome if we were to reintroduce top predators to help with the job?  We could then bask in the idea — as is Yellowstone National Park — that we again have a “complete” system.  Sorry, don’t hold your breath.  

“But they kill us, too.”  Poodles regularly go missing outside of Boulder, Colorado, but people don’t.  Since 2000, in the whole of North America only three people are known or believed to have been killed by Mountain lions.  The corresponding figure for Gray wolves is two (one in Alaska, one in Alberta, Canada).

So compare all of five apex predator human deaths in the last seventeen years with 114 Lyme-certified deaths between 1989 and 2004.  Could these reintroduced predators, coupled with human predation, reduce the Vermont deer heard enough to have an impact on Lyme?  Maybe, but between the income from “easy” hunting and the ancient, deep-brain terror of top predators, we will ignore the data, retain our incomplete forests, and live with a lot of deer.