Yellowstone Grizzlies To Be Counted Differently

U.S. Fish and Wildlife Service/Yellowstone National Park, Bear Hunting Magazine
03/26/2013

In the Greater Yellowstone Ecosystem, a new method for counting grizzlies could boost their numbers by 100 to 150 bruins. A Grizzly Bear Recovery Coordinator with the U.S. Fish and Wildlife Service stated that they believe their previous counts have been super conservative. The new method would allows a more accurate estimate in population size.

The agency is taking public comment on its proposal to implement the new counting method for bears in the ecosystem. The new method was developed over several years and was peer reviewed by bear specialists as well as mathematicians before being released to the public.

The initial methods used to calculate the population and mortality estimates for the Yellowstone Ecosystem were designed to address a sparse population in need of recovery, but the proposed changes allow them to use the best data available to carefully measure the health of a larger, more robust population.

The new method increases the science of the counts based on better technology. In addition to new ways to count bears, the Fish and Wildlife Service is proposing that bears outside of the region where the population estimate is made, no longer will be counted as dead bears within the recovery population.

The grizzly population in and around Yellowstone National Park has been estimated at around 600. As part of its search for a better method to count them, cooperators reviewed the past survival and cub productivity of bears and found in preliminary data that the population growth of the animals has slowed since 2001. The initial findings point to a lower survival rate among yearlings and possibly cubs while adult male survival has grown. Female survival has remained steady but the number of females giving birth to cubs declined slightly.

To address the change, the U.S. Fish and Wildlife Service is proposing to lower the acceptable mortality rate from 9% to 7.6% for female grizzlies at least two years old and dependent offspring.



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