Homer Alaska - News

Story last updated at 4:45 PM on Wednesday, February 29, 2012

Invasion of the hares



BY Hal Spence
For the Homer News


 

Photo by Michael Armstrong

A snowshoe hare in its color transition from winter to summer sits on the lawn of the Homer News last May.

So colorless it takes a keen eye to perceive them in the powder, when spotted, snowshoe hares can appear fragile and cuddly, their silence the quintessence of winter's quiet.

Then they butcher your trees.

The Kenai Peninsula is in the jaws, as it were, of a cyclical population explosion of Lepus americanus, creatures with voracious appetites that must be fed. This winter's heavy snowfall has reduced their food supply, and that has spelled disaster, even doom, for local shrubs and trees whose bark is tempting fare.

For most of North America, cycles between relative rarity and apparent over abundance take roughly a decade, according to U.S. Fish and Wildlife biologist Toby Burke, a biological technician with the Kenai Wildlife Refuge in Soldotna for seven years. Hare population monitoring on the Kenai Peninsula only began in 1983 and scientists are still accumulating data. Thus, pinning down the timing is still difficult, but it appears cycles here and in other parts of Alaska may take somewhat longer, perhaps as long as 15 years, Burke said.

What is clear today is that Kenai Peninsula environs favorable to snowshoe hares are supporting large populations, the highest, biologists believe, since the early 1980s.

"We are in the high part of a cycle," Burke said. "The question is are we at the peak or coming down? Most biologists say we're at the top, so we will start seeing decline. When they do (decline), they will do so rapidly."

Counting individual hares is next to impossible, so there is no good answer to the obvious question: "How many are there?" Researchers resort to recording their droppings by literally laying out grids within hare habitat and counting pellets by hand. While that gives you a figure useful for comparing peak periods, it does not translate quantitatively, that is, it does not tell you how many hares are around. There are methods for acquiring such a number, but they are time-consuming and expensive and "a nightmare," said refuge biologist Todd Eskelin. One has not been done since the 1980s, he said.

Naturally, food supply is critical for boosting and maintaining a population of hares. Areas burned within the past 10 to 15 years, where there is much young plant growth, appear ideal. Hares mostly forage at night, consuming succulent vegetation such as wildflowers, ferns and grasses during the verdant spring and summer, but chewing on twigs, small plants, evergreen needles and branch bark in the winter. When desperate, they'll strip bark from tree trunks, effectively killing them if the damage is sufficiently grave.

"Last winter we lost the creeping phlox that I planted. They ate everything down to the dirt," said Homer resident Judy Nester. "The hares ate all the Livingston daisies I planted." Nester, who was out of town when interviewed, said she was bracing herself for finding more damage when she returned.

"After the devastation from last winter, there is nothing left to damage this winter, literally," commented Rachel Livingston, of Homer.

Another resident, Mimi Tolva, said she sees "bunny parts all over my yard that the eagles have left behind." She worries that dogs can get worms from consuming the carcasses. "And the tiny little baby spruce trees, they ring them. They don't survive."

That's been the experience of many around Homer in recent winters. This season, efforts to trap and kill the creatures in order to protect stands of young spruce have sometimes snared several a night.

Homer resident Dave Gerard said he has some hare damage, but he's been actively protecting his plants.

"I have them (hares) stacked up like cord wood in my freezer," he said, adding that he intends to turn the hares into stew stock. Gerard has five acres near Fritz Creek, an area that had been logged. Now he's trying to protect young spruce trees. "Once they bark them, it's all over," he said.

Rene Alvarez said he's been shooting them with pellet guns, dispatching them as often as he can to protect what's left of his surrounding plant life. Hares have attacked his wife Susan's evergreens and ringed (stripped the bark from) 15 apple trees, likely killing them.

"They're just mowing through everything," he said.

Snowshoe hares prefer boreal habitat providing both cover from predators and easily accessible food. Areas burned within the previous 10 to 15 years are often ideal because the hares can easily reach most of the young growth.

"Generally speaking, you find more hares in early stages of forest establishment," Burke said. "But, even in years of abundance, there will be areas that won't yield many."

Hares generally tend to stay under heavy forest cover to avoid predators, but when the food runs scarce in such habitat, they'll risk increased exposure to predators to eat, a behavior that can contribute to their cyclical declines, he added. Predators thrive when hare numbers expand, lynx in particular.

"Lynx get the most notoriety," Burke said. "They're specialists."

The large-footed felines are aptly built for moving fast through deep snow in pursuit of snowshoe hares. When hare populations fall, Lynx will switch to spruce grouse or the occasional squirrel, but by and large, their numbers will move in tandem with those of the hares, Burke said.

Also feeding on hares are coyotes, wolves, foxes and an assortment of avian predators, including great horned owls, grey owls, northern goshawks, and occasionally eagles, though the strength of those populations is far less tied to hare numbers, Burke said.

On average, hares live a year, perhaps two, and females can bear young two or three times a year, with litters as large as eight. Mortality among the young is very high.

"Females produce volumes of young when there is good forage," Burke said. "The vast majority of young don't make it to their first birthday."

Hares' dietary habits can have another kind of biofeedback effect — on the plants they eat. Some plants react to continual browsing by producing toxins, Burke said, a biofeedback mechanism commonly triggered by moose that can also kick in when hare populations grow. The toxins render the bark less palatable and less nutritious.

Hares don't restrict themselves to typical winter fare. Unprotected garden ornamentals and exotics are easy targets.

While hare numbers increase rapidly when conditions are favorable, they also decrease rapidly.

"Within three or four years they could be scarce," Burke said.

Hares were very abundant last year within his subdivision just south of Kenai, but those numbers are not as high now, Burke noted.

"The reports I'm getting from the southern portions of the peninsula show that the numbers are a little higher than up here in Kenai, Soldotna and Sterling. That shows the numbers are not distributed evenly," he said.

While weather conditions, food supply and predator populations contribute to the ebb and flow of hare populations, scientists are still "scratching their heads" and working to determine the breadth and influence of population drivers, even investigating possible links to sunspot cycles, Burke said. There are a lot of hypotheses, but, as yet, no full-fledged theories, he added.

Hal Spence is a freelance writer who lives in Homer.

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