PROJECT TITLE: Bobcat and fisher habitat use and interactions I. PROJECT STATEMENT Fishers and bobcats are native carnivores that live in the forested region of Minnesota. Minnesota DNR data shows that over the last 20 years the fisher population has declined by about 50%. Dr. John Erb (furbearer biologist, MN DNR) radiocollared fishers from 2008 to 2015 and identified two potential causes of the fisher population decline in Minnesota: Cause 1: Limited availability of large-diameter cavity trees to support female fisher reproduction, and Cause 2: High rates of predation on fishers, mainly by bobcats To address Cause 1, the DNR supported the fisher den box proposal that we submitted to the LCCMR in 2018, and that project was recommended for funding (032-AH Den Boxes for Fishers and Other Nesting Wildlife). That project will start on July 1, 2019. The main objective of this project is to use data on fisher and bobcat habitat use, activity patterns, and diets to learn why female fishers are so vulnerable to being killed by bobcats, addressing Cause 2 for the fisher population decline. We used results of the DNR study and discussions with Dr. Erb to design our project. The relevant results of the DNR study include: - 21 of 26 fishers killed by predators in Minnesota were females, including 20 adult females - 15 adult female fishers were killed while caring for dependent kits, resulting in loss of all 15 litters - Bobcats are the primary predator of female fishers in Minnesota One reason for bobcat predation being important is that the bobcat population has more than doubled over the past 20 years while the fisher population has declined by 50% (See map page). The high rates of predation on female fishers documented by the DNR project are not sustainable. Understanding bobcat biology and why bobcats kill fishers will help to explain why the fisher population has declined and will help to identify management solutions to reverse the fisher population decline. The increase in the bobcat population is one obvious reason why bobcats would be killing fishers at high rates. Understanding why the bobcat population has increased will benefit management of both fishers and bobcats. The recent DNR project on fishers updated knowledge of the fisher population, but the last bobcat study in Minnesota was conducted almost 40 years ago, long before the bobcat population increased (see figure on map page). In addition to providing valuable information on the declining fisher population, our proposed project will also generate important information beneficial to management of bobcats, such as home range sizes, activity patterns, habitat use, and diet. Understanding why female fishers are vulnerable to being killed by bobcats will allow us to identify potential solutions that would help reverse the fisher population decline. This proposal is part of a larger effort to aid fisher management in Minnesota. We will deploy GPS collars on bobcats and fishers in Minnesota to: - Determine habitat use and activity patterns of bobcats and fishers - Identify habitats where bobcats and fishers are likely to come into contact - Collect prey and diet data to measure diet overlap and competition for prey - Evaluate factors contributing to the bobcat population increase over the last 20 years II. PROJECT ACTIVITIES AND OUTCOMES Activity 1: Determine habitat use, diets, and activity patterns of bobcats and fishers to inform management options Budget: $440,719 We will capture and deploy GPS collars on 24 bobcats and 28 female fishers in two study areas where previous fisher research has taken place. We will use GPS location data from study animals to describe fine-scale habitat use and identify areas where fishers are vulnerable to predation by bobcats. Locations will also be used to identify and to monitor reproductive dens used by fishers and bobcats, and to determine why bobcats kill fishers during the breeding season. We will collect data on bobcat and fisher diets and prey availability to measure prey competition between bobcats and fishers. We will summarize home range sizes and overlap, survival and causes of mortality, and activity patterns of bobcats and fishers we radiocollar. Lastly, we will use existing data on bobcat and fisher harvests from the DNR and historical forest change data to identify changes in bobcat and fisher distribution over time and determine the role of forest change in recent population trends. Outcome / Completion Date 1. Deploy GPS collars on fishers and bobcats over 2 capture seasons / February 2022 2. Monitor habitat use to identify areas where bobcats and fishers encounter each other / March 2023 3. Collect and analyze diet samples from radiocollared bobcats and fishers / March 2023 4. Finalize analyses of habitat use, diets, and activity patterns and submit final reports / June 2023 III. PROJECT PARTNERS Dr. Michael Joyce (NRRI-UMD) is overall project manager and will design and implement all aspects of this project including live-capture of study animals, field-monitoring, and data management and analysis. Dr. Ron Moen (NRRI-UMD) will provide input and assistance to Dr. Joyce on all aspects of this project. Dr. John Erb (MN DNR) will provide input and in-kind support on this project, with intent to use results to help inform fisher and bobcat management Dr. Roger Powell (North Carolina State Univ.) will provide input and in-kind support on this project IV. LONG-TERM-IMPLEMENTATION AND FUNDING: This proposal is part of a larger effort to understand fisher ecology in Minnesota. This project will build off the results of the DNR fisher project and complement our ongoing fisher den box project that was recommended for funding by LCCMR last year. Radio-collaring female fishers near den boxes will provide additional data to understand factors influencing whether fishers use den boxes, while information on where fishers are vulnerable to predation by bobcats will help guide future fisher den box deployments. The bobcat population increase is a management success story, but it appears to have come at a cost to fishers. Data on fine-scale habitat use and diets of bobcats and fishers in the same area are important for understanding why bobcats are killing fishers and for developing management strategies to promote the fisher population while maintaining a healthy bobcat population in Minnesota. This project will generate foundational data that the DNR can use to manage fisher and bobcat populations in Minnesota. GPS data on fine-scale habitat use by fishers and bobcats has never been collected in Minnesota, and this project will generate valuable data on bobcats that has not been collected in Minnesota for >35 years. TIMELINE REQUIREMENTS This project would require three years of ENRTF funding from 7/1/2020 to 6/30/2023. We will focus live-capture and radiocollaring efforts during the first two years of the study, and we will monitor study animals for all three years. We will focus on field data collection during the first 2.5 years and complete analyses and reporting during the final 0.5 year.