Mule Deer Emmett Migration Maps and Statistics

This analysis uses location data collected on mule deer that were fitted with GPS collars in Idaho for 2003 – 2019. Individuals using a winter range (as defined as a winter herd), were used for the analysis if their location data was available at the time of the analysis. Each individual’s location dataset is used to estimate winter and summer ranges, and seasonal spring and fall migration using net-squared displacement techniques (Bunnefeld et al. 2011). Fall and spring migration locations are used for the migration route analysis. After individual mule deer spring and fall migration locations are determined, a Brownian Bridge Movement Model (BBMM, Horne et al. 2007) is used to estimate the individuals Utilized Distribution (UD) during the seasonal migrations. Depending of the frequency of the location data, either a BBMM or a Forced Motion Variance model (FMV) are used as an estimate of that season’s migration UD. If locations collected at a 7hr schedule, the migration used BBMM modeling techniques. If the schedule was greater than 7 hrs a FMV modeling technique was used (Fatteberge et al, in review). Further, FMV techniques that allowed for a 14 hour gap in location schedule were preferred over FMV models that used a maximum of 27 hr gap. When an individual had several seasonal migrations, the resulting UDs distributions are combined and averaged to create a single UD of all the seasonal migrations conducted by that individual. Individual UDS are then combined for all individuals in the winter herd with available UD information. For migration routes, the following classes were delineated based on the area’s use across the winter herd, used by 1 individual, used by 2individuals to 10% of the winter herd, 10 to 20% use of the winter herd, and greater than 20% use by the winter herd. The combined individual UDS are aggregated to estimate winter herd stopover locations. From the combined winter herd UD, the top 10% of recorded values are selected to represent population level stopovers. Emmett Mule Deer Migration Statistics Analyzed/Prepared by: Jodi Berg and Scott Bergen December 2019 Spatial Metrics Average Migration Length: 42.022 miles Maximum Migration Length: 85.756 miles Minimum Migration Length: 12.777 miles Total Migrations Analyzed: 146 Total Number of Individuals: 60 Total Number Spring Migrations: 85 Total Number Fall Migrations: 61 Of 146 individual seasonal migrations, 11 used Brownian bridge movement models with an 8-hour time-lag, 53 used forced motion variance (1000 m) models with a 14-hour time-lag, and 82 used forced motion variance (1000 m) models with a 27-hour time-lag. Temporal Data Extent of Study: March 16, 2003 – December 28, 2018 Spring Migration Fall Migration Start Date Average March 25 October 17 Minimum January 31 May 26 Maximum April 26 December 2 End Date Average May 2 November 1 Minimum February 23 October 13 Maximum July 2 March 8 (following year) Duration Average 31 days 20 days Minimum 4 days 3 days Maximum 77 days 147 days Migration Use Class Statistics Use Class Acres 1 individual 951,384 Low (>2 individuals) 455,751 Medium (10-20%) 169,634 High (>20%) 52,262 Stopover 51,965