In the spring of 1992, Twin Falls Resort State Park officials erected a deer exclosure to show the difference between the foliage inside and outside the small fenced area near picnic shelter 1.

A few months after the exclosure was erected, the difference wasn’t dramatic to visitors. Today, however, the exclosure — even in winter — is filled with vegetation the deer can’t reach.

Park visitors reported seeing as many as 200 to 250 deer as they drove through the park during the 1980s and early 1990s.

“Now, you might see 15,” said park Superintendent Scott Durham.

At the time, Durham explained, the large deer herd on the park were over-browsing the food supply. As a result, he predicted then, the deer would destroy their future food supply and die from disease and parasites due to malnutrition.

“That didn’t happen,” Dur-ham said last week. “What did happen is the deer stopped reproducing.”

The hormonal change, resulting in reduced deer reproduction on the park, is indicative of the general nutrition and health of the herd.

It is also another response to a reduced food supply — just like diseases and parasites, the superintendent said.

“We have observational evidence to support this,” emphasized Durham, who is a wildlife biologist.

Diseases and parasites would have resulted in a mass die-off, Durham said.

“We didn’t have a mass die-off here on the park,” he explained.

There have been periods on the park — in the 1990s — when officials found numerous dead deer, sometimes as often as one a day.

Additionally, Durham said, in the 1980s, there were numerous sets of twins and even triplets born to deer on the park.

“That was when there was growth in the herd. Now all we see are singles,” Durham said. “We hardly ever see twins now and never see triplets.”

The lack of availability of nutritious food is also resulting in much smaller racks on the deer as well as smaller animal sizes.

“Today, the deer are surviving on grass, which has a very low nutritional value,” Durham emphasized.

The carrying capacity of the park has fallen well below what it takes to sustain the deer herd in terms of food, Durham noted.

The carrying capacity is the maximum population size that can be sustained indefinitely by available food and water sources.

The deer browse, or eat the plants, as they make their way over the park, Durham said.

“They browse their habitat, nipping and biting as they go,” he explained.

As a result of the smaller herd size, park officials are seeing the regrowth of the park plant life.

“We’re seeing seedlings and tree regeneration. We’re seeing wild flowers we’ve haven’t seen on the park in years. These are all signs the areas aren’t being over-browsed now,” he said.

It’s all part of the natural cycle.

“In 1974, deer were stocked on the park. Then, the park habitat was perfect; there was an abundance of food with a high nutritional quality.”

Durham said the deer herd was about 166 at that time.

“Then, the population went crazy, and, when the food went away, over a period of time, the deer population got smaller. I am surprised at how fast it happened,” Durham said.

The deer population will naturally adapt.

Although the herd is currently becoming fewer in number, at some point, the numbers will increase when the food supply improves.

“Nature moves in cycles,” Durham said.

When there is a big improvement in the food supply, the deer will again overrun the carrying capacity — but by less than they did so previously.

Then, the herd will hover at the correct carrying capacity, barring any unforeseen factors, such as a dramatic climate change, he emphasized.

“Nature is a dynamic force that is constantly changing,” Durham noted. “To adapt, the animals are constantly changing. Nature is a never-ending dance of change.”