This project addresses issues associated with mule deer population dynamics and competition with ELK

The State of Oregon Department of Fish and Wildlife (ODFW) received a $2.49 million formula grant from the U.S. Department of the Interior Fish and Wildlife Service under the Wildlife Restoration and Basic Hunter Education and Safety program (CFDA 15.611) for the period of July 1, 2025 through June 30, 2026. This grant supports a multi-phase research initiative investigating mule deer population dynamics and the competitive interactions between mule deer and elk populations in Oregon. The project delivers comprehensive wildlife management research services including population monitoring through continued collar-based tracking (eleventh year of collaring activities as of winter 2025-2026), measurement of population metrics such as pregnancy rates, fawn survival, and doe survival, and assessment of winter nutrition impacts on mule deer populations at the Starkey Experimental Forest and Range.

The research directly informs wildlife management decisions through controlled experimental manipulation of elk populations and supplemental feeding protocols. ODFW compares baseline population data collected during Phase I (2013-2019) against post-intervention data from Phase II (initiated 2020), wherein elk populations were reduced by approximately 85% to determine whether mule deer exhibit positive population responses. This investigation of competition-driven population limitation and nutritional factors produces evidence-based findings essential for effective mule deer management across Oregon and the Western United States, supporting the species' significant recreational, aesthetic, ecological, and economic values.

Mule deer have high recreational, aesthetic, ecological, and economic values in oregon and the western united states. Effective management of mule deer requires an understanding of basic population metrics such as survival and recruitment of fawns into adult age classes and factors that influence those metrics. This research project will estimate mule deer population metrics including, but not limited to, pregnancy rates, fawn survival, and DOE survival. The objectives of this research are to determine: 1) the effects of competition with ELK and 2) winter nutrition on mule deer population dynamics. This research will occur in two phases. During phase i (2013-2019), we collected baseline population data (e.g., body condition, pregnancy, and survival) on mule deer. We will enter our eleventh year of collaring mule deer during winter 2025-2026. During phase II (which began in 2020), we reduced the ELK population in the starkey experimental forest and range by 85% to determine if mule deer respond positively to reductions in ELK density. We reduced the ELK population during winter of 2019 2020 by approximately 50% and achieved an 85% reduction during the winter of 2020 2021. Following additional data collection during years with low ELK densities, we will compare pregnancy rates, fawn survival, and DOE survival before and after a reduction in ELK populations. Any increase in mule deer population performance following reductions in ELK populations, will provide compelling evidence that mule deer population growth is limited by competition with ELK. Our research is also designed to determine the effects of winter nutrition on mule deer population dynamics. Mule deer that voluntarily enter the winter handling facilities at the starkey experimental forest and range are provided supplemental feed during winter. Deer that overwinter in main study area will not receive supplemental feed. We will compare pregnancy rates, fawn survival, and adult survival of these two groups to determine if winter forage and nutrition is limiting mule deer population dynamics. If this limitation is observed, IT will suggest winter forage conditions are not sufficient to meet the energetic demands of mule deer.