Fall’s the season for monitoring our state’s moose

Published 1:30 am Sunday, October 9, 2016

Jared Oyster is a practical man.

Faced with a bull moose courting a female — one that didn’t appreciate any competition, even if it was a human — Oyster quickly assessed the situation.

“The bull wasn’t happy that I was there. He ran me off, grunting, shaking his antlers,” he said. “I decided that he won.”

This is hunting season for moose, so the state Department of Fish and Wildlife biologist is heavy into sampling moose heads harvested by hunters. Oyster is sampling for an arterial worm that’s prevalent in Western moose but not yet showing up in large numbers in Washington.

It’s a worm that spends its life in the arteries, particularly where the carotid artery branches into the brain. If the worm population is high enough, it can block blood to the brain, creating havoc in many forms, including blindness.

In this state, only two of 67 samples had worms; in Wyoming, it’s about 50 percent of the samples. “We don’t understand the worms physiologically. That still needs research,” he said.

There are about 3,000 moose in the state, scattered mostly in the northeast corner. Researchers track cows wearing tracking collars and GPS transmitters, so researchers can locate them in real time.

Worms aren’t the only challenge for moose across the northern tier of the continental United States. Moose also must deal with climate change.

“The best weather for moose is colder weather. There are two reasons. Moose have a thick dark coat that absorbs heat and that can cause physiological stress. And warmer weather means a longer growing season (for plants) and fewer days below freezing, which means a higher parasite load because ticks won’t be killed as quickly by freezing,” Oyster said.

During a longer growing season, “more ticks congregate on the top of vegetation, and so more ticks are on the moose,” Oyster said.

This is no mere annoyance. I had to ask the question twice because I couldn’t fathom Oyster’s answer. How many ticks might be on one moose? Oyster: 30,000 to 50,000.

“The drain on blood can be hard on a moose, particularly for calves. For them, up to 50 percent of the blood volume might be taken.”

Moose try to rub off the ticks but the energy spent on scratching off the ticks means less time resting and foraging.

While moose populations in other states are declining, Washington’s have been increasing since the 1970s, although that may be leveling off, Oyster said.

In other states, a combination of parasites, heat stress and predation are causing the decline. As might be expected in a growing population, moose have been interacting more with humans.

“We get calls almost daily, especially around Spokane,” Oyster said. “Mostly they don’t cause problems unless they’re trapped (highways, fences) and we have to remove them. And that’s dangerous for the moose, neighbors, and us. We’re trying to get to the point that residents have tolerance for the moose.”

A few facts about moose:

Most of the moose live in Pend Oreille, Stevens, Ferry and Spokane counties with smaller populations in the North Cascades, Okanogan and Blue Mountains.

The word moose came from a Native American tribe, the Algonquin, and translates into “twig eater” because they eat mostly twigs, bark, and leaves of brushes, although they will eat aquatic vegetation and willows.

Breeding occurs in the fall, with the rut typically beginning around mid-September to early October.

Most of the time, snow is not a problem for moose because they have long legs and a high chest.

Information: wdfw.wa.gov/living/moose.html.

Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.