An in-depth review of the history of sage grouse hunting and population trends across the Intermountain West has shown that a significant decline in the bird’s numbers during past decades prompted important changes in hunting season regulations in order to protect the endangered birds.
In a study published in the journal PLOS One, a research team investigated the history of grouse hunting regulations in 11 U.S. states and two Canadian provinces, as well as the impact of these regulations on growth rates of this species.
Once numbering millions across the Intermountain West, sage grouse populations dwindled in the first decades of the 20th century, prompting wildlife agencies to impose hunting restrictions in the 1930s and 1940s. These restrictions included reducing possession limits and hunting season lengths, and setting season starting dates later in September in order to avoid the killing of females with young broods.
“We found that wildlife agencies throughout western North America have set increasingly more conservative harvest regulations over the past 25 years to conserve sage grouse,” said study co-author Jeffrey Beck, a professor of Wildlife Habitat Restoration Ecology at the University of Wyoming.
“It appears that, overall, agencies are doing well with adjusting the timing of hunting seasons, reducing season lengths and maintaining later hunting seasons as supported by previous research,” added study lead author Jonathan Dinkins, an assistant professor of Agricultural Sciences at Oregon State University.
“Also, by retaining hunting seasons but lowering bag and possession limits, agencies continue to bring in important funding for conservation from hunting permits while ensuring hunter take is limited to sustain populations.”
However, regarding the overall effect of hunting season regulations on population growth rates, the scientists found mixed results: although discontinuing harvest in the largest sage grouse population in Idaho resulted in greater population growth rates, this was not the case for smaller populations.
In a separate study published in the same journal, the researchers also assessed the impact of weather conditions, human activity such as oil and gas development, and habitat loss due to fires on population trends. The team once again found that not all sage grouse populations were influenced by the same factors in the same ways.
Although these studies come with mixed results, the researchers hope that their models will help management agencies better understand population trends and focus conservation efforts on factors that may lead to increasing the survival and reproduction rates of endangered birds.