Description: Researchers examine how the regulation of coyotes affects the fawn mule deer population in Utah. For more information, visit the BYU News coverage of this project at https://news.byu.edu/news/study-newborn-fawns-seeks-insight-population-declines.
- Start: January 1, 2012
- End: June 30, 2017
- Sponsor: Utah Division of Wildlife Resources
- Principal Investigator: Brock McMillan
- Co-PI: Randy Larsen
Mule deer are a common type of deer to Utah and reside all throughout the western side of North America. They are uniquely identified by their large, mule-like ears, for which they are named. While Utah’s population of mule deer was estimated to be just over 330,000 in 2013, the Utah Division of Wildlife Resources (UDWR) hopes to achieve a long term population of over 400,000 mule deer.
In collaboration with Professor Julie Young at Utah State University, BYU Professors Brock McMillan and Randy Larsen are investigating how the Utah mule deer population is specifically affected by the control of predators. In this study, the research team is focusing on the coyote population as a predatory factor, although they recognize that many other factors contribute to the population growth or decline. Other influences include harsh weather, food scarcity, disease, habitat loss, and even the classic deer-in-the-headlights vehicle accidents. Working with the UDWR, the research team is investigating the effect predators have on the population through the survival of newborn mule deer.
The study consists of a control site and a treatment site in which the populations of both coyotes and mule deer are monitored. The treatment site experiences coyote removal techniques from the USDA Wildlife Services, while the control site is unaltered. Coyotes from both sites are tagged and monitored. Other population estimating techniques are also employed to ensure accurate data when analyzing the results, since both coyote populations are likely to be additionally affected by natural factors or other sources. By comparing survival rates of newborn deer in both the control and treatment sites, the researchers hope to draw conclusions based on the number of coyotes in the area and corresponding fawn (newborn deer) population at each site.
The researchers and their teams monitor the populations of mule deer based on the birth and survival rates of a selected sample in the population. Each year for four consecutive years, the team captures, collars, and releases about 40 does (adult female deer). Each deer is fitted with a VHF (very high frequency) collar. This method allows the researchers to locate the deer through pulsing radio frequencies emitted from the collars. Each year, fawns are typically born in the second and third weeks in June. The researchers monitor the female closely during this time, as well as the fawns once they are born. Each doe is also positioned with a VIT (vaginal implant transmitter). The VIT transmitter leaves the doe and becomes activated after she gives birth. Through the transmitter, the researchers are able to locate the birthing site, as well as the newborn fawn, who are also monitored with an expanding collar. If a fawn dies, the researchers record and investigate the cause of its death.
The researchers hope to gain a better understanding of the role predators have on the mule deer population here in Utah. In addition, the team also expects to learn the effectiveness of using VIT transmitters on newborn deer, comparing this method with more traditional methods of the location of fawns. From their study, other statistics regarding the deer population will be obtained, including causes of newborn deer mortality, ratio of male to female fawns born, and approximate dates of birth for the current mule deer population. The collaborators on the project anticipate the publication of at least four reports and multiple conference presentations on their findings.