IDFG releases mule deer composition survey data for southwest Idaho

The Idaho Department of Fish and Game (IDFG) completed its annual mule deer herd composition surveys in southwest Idaho last December, focusing on key winter ranges to look at the health and vitality of herds. Biologists tallied overall populations with a specific look at buck numbers and buck-to-doe ratios as well as fawn survival rates in the Central Mountains, Weiser-McCall, Owyhee, and Smoky-Boise Data Analysis Units (DAU), according to a news release. 

They discovered that fawn ratios were similar or slightly above the long-term average, with the results from Weiser-McCall being “noteworthy” as it was the highest fawn-to-doe ratio since 2011. Biologists discovered a similar increase in the fawn-to-doe ratio in the Smoky-Boise DAU (71 fawns:100 does) in 2024 – which is an increase of about 13% compared to the long-term average and up 7% from 2023. While this is usually good news, winter could still impact fawn survival rates. 

IDFG is currently monitoring mule deer within the Smoky-Boise DAU, particularly Unit 39, as there have been indications of the area “nearing carrying capacity” and fawn weights were “below average” in this area, meaning that the deer may be “competing for limited resources.”

“Skinny fawns are less likely to survive the winter, which means that the higher fawn:doe ratio in the Smoky-Boise DAU during the herd composition survey in December may not directly relate to more bucks in the fall,” said Ryan Walrath, IDFG regional wildlife manager. “We will need to wait to see how the winter affects fawn survival through May 2025.”

Abundance surveys for mule deer in the Smoky-Boise DAU and elk in the Brownlee and Weiser-McCall elk zones are currently underway. Stay tuned to GOHUNT for more information!