The southern fox squirrel (Sciurus niger niger) has the northernmost part of its range in Virginia. For the past 100 years, southern fox squirrels have been declining due to habitat fragmentation, cover type conversion, and fire suppression. Decrease in growing season burns, hardwood encroachment and forest mesophication have transformed pine hardwood woodlands and pine (Pinus spp.) savanna habitats that southern fox squirrels prefer to hardwood dominant habitats that eastern gray squirrels (Sciurus carolinenisis) prefer. These habitat changes have the potential to increase competition among the two species. The main objectives of my study were to investigate the general resource needs, occupancy, and home range of southern fox squirrels as well as the impact of resource partitioning and possible competition with eastern gray squirrels in the Piedmont and Coastal Plain of Virginia. I captured, radio collared and tracked four individuals at Big Woods Wildlife Management area and Piney Grove Complex using 95% and 50% kernel density estimate. I found an average male home range 173.49 ha (SE = 25.73, N = 2) and 40.62 ha (SE = 5.87, N = 2) and an average female home range of 28.51 ha (SE = 0.49, N = 2) and 4.71 ha (SE = 0.34, N = 2). I then identified the second and third order habitat selection in which my top models identified selection for pine savanna cover types (β = 2.095, SE = 0.158), increasing number of burns since 2019 (β =1.24, SE = 0.098), and decreased time between burns (β = -0.233, SE = 0.097). I used two-species occupancy modeling which reflected that gray squirrel occupancy increased with increasing time since last prescribed burn. However, southern fox squirrel occupancy, in the absence of gray squirrels, decreased with increasing time since last burn. My informed single-season occupancy model confirmed that southern fox squirrel occupancy decreased with time since the last burn. Presence in the absence of gray squirrels suggests that southern fox squirrels are selecting habitats on BWPGC with respect to both resource needs and competition with gray squirrel. Additionally, my level-of-effort (LOE) analysis indicated that 7 consecutive days of camera trapping without a southern fox squirrel detection would provide 90% confidence of the species' absence in areas burned 2 or more years prior to sampling in southeastern Virginia. Further management for southern fox squirrels in the future should focus on high rotational (short fire return interval) burns in areas of savanna as well as pine-hardwood mixed areas and hardwood-pine savanna ecotones. / Master of Science / The southern fox squirrel (Sciurus niger niger) is a subspecies of fox squirrel that ranges from southeastern Virginia down to northern Florida. All throughout its range in the Southeast, southern fox squirrel habitat has been fragmented from natural mixed pine-hardwood woodland forests to agriculture and high rotation pine plantations. Additionally, habitat has been further transformed by the lack of prescribed fire as a management tool on the landscape. This has in turn created sparse and fragmented local populations of southern fox squirrels as well as possible competition with gray squirrels. Further, the southern fox squirrel has not been studied in Virginia in over 20 years and management recommendations are lacking. I studied the resource needs, occupancy, home range and competition of southern fox squirrels in two physiographic regions of Virginia: the Coastal Plain and Piedmont regions. The Coastal Plain field site was Big Woods Wildlife Management Area and The Nature Conservancy's Piney Grove- both adjacent to each other. The Piedmont field site was Military Training Center Fort Barfoot. Here I utilized camera trapping, nest box monitoring, live trapping, and radio tracking to assess the resources they are utilizing in each area through home range analyses. I found that southern fox squirrels are selecting areas that have low fire return intervals and are located in pine savanna habitats. Therefore, fire should be prioritized as a management tool for southern fox squirrel habitat in pine savanna areas. I also used camera trapping data to identify the possible competition among gray and fox squirrels and fox squirrel detection through occupancy modeling. My findings reflected that there is apparent competition between southern fox squirrels and eastern gray squirrels and that southern fox squirrels are selecting heavily burned areas not only for their resource needs, but also because gray squirrels are absent. I concluded through my studies that the southern fox squirrel currently occupies southeastern Virginia, particularly in the Coastal Plain, however at low numbers. This could be due to suitable habitat on Big Woods/Piney Grove, but the surrounding habitat is of marginal quality. Further, in documenting southern fox squirrels, multi day camera surveys in mixed pine-hardwood woodland and pine savannas should be prioritized. Also, in aims to increase the presence of southern fox squirrels on the landscape, short rotation prescribed burning should be prioritized as well as additionally considering meditation among gray squirrel and fox squirrel competition.

Habitat modeling can assist in managing potentially widespread but poorly known biological resources such as the federally endangered Delmarva fox squirrel (DFS; Sciurus niger cinereus). The ability to predict or identify suitable habitat is a necessary component of this species' recovery. Habitat identification is also an important consideration when evaluating impacts of land development on this species distribution, which is limited to the Delmarva Peninsula. The goal of this study was to build a predictive model of DFS occurrence that can be used towards the effective management of this species. I developed 5 a'priori global models to predict DFS occurrence based on literature review, past models, and professional experience. I used infrared photomonitors to document habitat use of Delmarva fox squirrels at 27 of 86 sites in the southern Maryland portion of the Delmarva Peninsula. All data were collected on the U.S. Fish and Wildlife Service Chesapeake Marshlands National Wildlife Refuge in Dorchester County, Maryland. Preliminary analyses of 27 DFS present (P) and 59 DFS absent (A) sites suggested that DFS use in my study area was significantly (Wilcoxon Mann-Whitney, P < 0.10) correlated with tree stems > 50 cm dbh/ha (Pmean = 16 + 3.8, Amean = 8+ 2.2), tree stems > 40 cm dbh/ha (Pmean = 49 + 8.1, Amean = 33 + 5.5), understory height (Pmean = 11 m + 0.8, Amean = 9 m + 0.5), overstory canopy height (Pmean = 31 m + 0.6, Amean = 28 m + 0.6), percent overstory cover (Pmean = 82 + 3.9, Amean = 73 + 3.1), shrub stems/ha (Pmean = 8068 + 3218, Amean = 11,119 + 2189), and distance from agricultural fields (Pmean = 964 m + 10, Amean = 1308 m + 103). Chi-square analysis indicated a correlation with shrub evenness (observed on 7% of DFS present sites and 21% of DFS absent sites). Using logistic regression and the Information Theoretic approach, I developed 7 model sets (5 a priori and 2 post hoc) to predict the probability of Delmarva fox squirrel habitat use as a function of micro- and macro-habitat characteristics. Of over 200 total model arrays tested, the model that fit the statistical, biological, and pragmatic criteria postulated was a post hoc integrated model: DFS use = percent overstory cover + shrub evenness + overstory canopy height. This model was determined to be the best of its subset (wi = 0.54), had a high percent concordance (>75%), a significant likelihood ratio (P = 0.0015), and the lowest AICc value (98.3) observed. Employing this predictive model of Delmarva fox squirrel occurrence can benefit recovery and consultation processes by facilitating systematic rangewide survey efforts and simplifying site screenings. / Master of Science