Understand the biology before making judgements

Alaska’s predator control program hasn’t received much press recently except for some articles mentioning the continuing lawsuits against the program.

Generally, though, the program has been running “under the radar” from a public relations point of view because not much has been happening. I expect that will change when the wolf control portions of the program become active again this winter.

The program operates on the theory that when prey population numbers become low enough, the only way to grow the population back to a healthy and self-sustaining number is to reduce the loss of animals from that population. In Alaska those prey populations usually consist of moose and caribou herds and things like predation, winter kill, disease, habitat loss, and hunting are some of the factors taking animals out of the population.

The wildlife managers do control and restrict hunting activity and that is normally the first step taken to protect a population of concern. Depending on the situation, they can sometimes influence habitat conditions by controlled burning or logging to create improved habitat. Things like disease and severe winter weather are generally beyond human control to any significant extent.

Just as the managers can manipulate the numbers of moose or caribou in a population by regulating the harvest of bulls, specifying antlerless-only hunts or setting harvest limits at so-many animals per season, they can also manage and manipulate the numbers of predators removing animals from the prey population of concern.

In Alaska, wolves and bear are the major natural predators of moose and caribou. Both of these predators are opportunistic hunters, that is, they will test any animal they find and will kill it if the situation allows. The idea that the predators only take the old and the weak is a warm, fuzzy thought but is not true in the real world.

Studies found that bears especially target moose calves and can kill 90 percent or more of each year’s calf crop in a population. With that level of annual loss, it should come as no surprise the population can’t grow back to a healthy and self-sustaining number of animals!

Wolves take any animal; they don’t key in on any particular subgroup like the bears do. However, wolves kill their prey all year long while bears have their greatest effect during the six to eight-week period when the calves are born and, of course, don’t kill anything while they hibernate during the winter.

The only way to reduce the loss of animals to these two predators is to reduce the number of predators. The intent is not to eliminate either bears or wolves, just reduce the numbers enough so that, over a five to ten year period, the moose or caribou populations can grow back in sufficient numbers to also support a healthy predator population. Studies have shown this approach works.

That’s the very simplified biology.

Now we have the social aspects. Many people don’t understand how nature works and they view wolves and bears as victims in this management approach. The battle continues in Alaska over the understanding and acceptance of the predator control program.

We are not unique in Alaska with this problem!

I recently read an article about how coyote populations east of the Mississippi are having significant impacts on whitetailed deer populations in some states.

Coyotes are not native to the eastern states. They have been expanding their range eastward over the last 100 years or so since the elimination of the eastern red and gray wolves has occurred. Recent studies in Georgia, South Carolina, and Alabama have shown that coyotes are especially tough on fawns during the first six weeks of life. These same studies have also documented a staggering jump in fawn abundance after trappers removed significant numbers of coyotes from the study areas. In one area, two fawns were present for every three does in the predator-removal section where only two fawns were present for every 28 does in the section where no predators were removed.

An older study, done in 1995, concluded that coyote predation accounts for 30 percent of Maine’s annual deer mortality. One of the biologists involved in this study was my office mate from my days in graduate school in Maine. Gerry Lavigne reported that coyotes were more likely to limit deer herd size in areas where winter habitat quality is severely reduced. He further warned that when deer are below population goals, coyote predation can keep the numbers below normal or even reduce them further. Sounds like what I was just talking about with bears and wolves in Alaska!

After describing some habitat manipulation to protect the fawns from coyote predation, the article continues, “Such efforts might be futile, however, if deer numbers are already low and coyote numbers are high. Hunting and trapping is likely necessary, but it’s not a one-shot solution. Research suggests reducing the coyote population by more than 75 percent before the annual fawning season. Then, expect to carry out aggressive culls annually because coyotes bounce back fast.”

The animal populations are different, but the biological principles are the same. Consider this: maybe our Alaskan managers really do know what they’re doing.

Howard Delo is a retired fisheries biologist with the Alaska Department of Fish and Game. You can leave him a message by e-mailing sports@frontiersman.com.