Bear study to determine best way to monitor, age Panhandle populations
(Photo courtesy IDFG) University of Idaho and IDFG biologists are working on a study to determine how best to pinpoint bear density in parts of Idaho including the Panhandle. The study will use collars and trail cameras, and also seeks to learn how berry crops effect bear reproduction.
(Photo courtesy IDFG) Biologists collar a black bear during an earlier black bear study in the Panhandle that used hair samples to help monitor bears in parts of North Idaho.
A North Idaho bear study will help biologists find new ways to monitor Panhandle black bear populations, and better pinpoint bear density.
Since April, biologists from the University of Idaho have worked in conjunction with Idaho Fish and Game to trap and collar Panhandle black bears in Unit 6 and begin setting up trail cameras for a three-year study that will also monitor the effects berry crops have on black bear reproduction, Barb Moore of Idaho Fish and Game said.
“The focus is to determine if remote cameras can be used to estimate bear density and cub recruitment and how strongly berry abundance and diversity affects cub recruitment,” Moore said. “We’re trying to understand the relationship between how bad berry crops need to be to block implantation.”
Aside from a few black bear studies over the past several decades, Idaho Fish and Game usually relies on harvest data to estimate black bear populations. North Idaho’s mostly vertical and often roadless terrain makes monitoring difficult and costly.
The latest study will pool information gathered in two additional study areas including an area around Dworshak Reservoir and the North Fork of the Clearwater River in Unit 10A, and an area from New Meadows south to the Boise River in Unit 32A, to narrow down the best way to track bears, which may include setting up trail cameras in popular areas such as around natural food sources.
“Black bears are difficult to monitor,” Moore said. “They are relatively solitary most of the year, they are relatively low density, they are a difficult species to get a lot of information on.”
Moore was one of the biologists who worked on a Panhandle bear study in the mid-2000s that used hair sample collection sites to determine bear movement. The study found that bears from outside the normal gene pool moved widely through North Idaho during years of berry crop failures.
Bears mate in the spring, but fertilized eggs don’t attach to the uterine wall until a sow has the nutrients to ensure a healthy cub. Delayed implantation is influenced, biologists believe, by the ampleness of a food source, such as the Panhandle berry crop. When huckleberries, service and buffalo berries are abundant, biologists believe, delayed implantation occurs more readily. Usually fewer cubs are observed in the years following a failed berry crop.
Although the current black bear study will not use DNA samples from hair, earlier studies tracked bears using hair samples collected at a number of stations that used wire mesh to catch hair from passing bears. Genetic information helps biologists determine how genetically diverse a population is, Moore said.
“Generally speaking, the more genetically diverse a population is the more healthy it is,” she said. “And the better (its) chance of withstanding catastrophic events or significant environmental changes.”
North Idaho bear populations have been stable over the past several decades with small fluctuations that in many cases follow berry crop abundance.
Panhandle hunters in 2017 harvested 673 black bears, or 7.6 black bears per 100 square miles. Most hunters used bait where it was allowed and harvested bears during the spring hunt.
Statewide, the 2017 harvest was lower than a year earlier, but above the previous 10-year average, according to Idaho Fish and Game.