SEAFWA 2015

Jared Beaver, Craig Harper, Lisa Muller, P. Seth Basinger, Matthew Goode –University of Tennessee; Frank T. van Manen, U.S. Geological Survey

Use of infrared-triggered camera (hereafter; camera) surveys for white-tailed deer (Odocoileus virginianus; deer) population density estimation, while popular among land managers, does not currently provide an estimate of precision critical for accurate density estimation. We believed that incorporating spatial aspects of sampling into the analytical process would allow a means for providing both estimates of precision associated with density estimates and an ability to calculate effective capture area. We conducted camera surveys for deer in Units 1 (1,385 ha) and 2 (1,488 ha) at Arnold Air Force Base, Tennessee, USA, August 2010. We used spatially explicit capture-recapture (SECR) data with Program DENSITY to fit a spatial detection function (g0; probability of detection at a single detector at a distance from the center of the home range) and estimate antlered male density from individuals identified based on antler criteria. Antlered male density estimates were similar between camera surveys using traditional sampling techniques (abundance estimated based on recaptures of recognizable antlered males from camera images; 2.0 males/km2 and 2.6 males/km2) and SECR density estimation (1.6 males/km2 [SE = 0.33, g0 = 0.24] and 2.5 males/km2 [SE = 0.56, g0 = 0.14]), for Units 1 and 2, respectively. Both estimation methods indicated lower deer density in Unit 1 versus 2. Analysis of camera surveys using spatial modeling uses the data from the spatial distribution of cameras and does not require the assumption of equal detectability. Use of spatial modeling can improve current camera survey methods by providing both a measure of precision that is currently lacking from traditional camera analysis methods and including spatial distribution of captured deer. Spatial modeling should be explored further as a possible means of enhancing our understanding of potential biases associated with behavioral responses to the use of bait as an attractant.

Jeffery D. Sullivan, Stephen S. Ditchkoff – Auburn University; Bret A. Collier, Louisiana State University; Charles R. Ruth, South Carolina Department of Natural Resources; Joshua B. Raglin, Norfolk Southern Railway, Brosnan Forest

White-tailed deer (Odocoileus virginianus) are predominately crepuscular; however, the general populace believes that deer activity is also influenced by lunar factors. This belief is demonstrated by the countless “solunar charts” claiming to provide peak periods of deer activity. However, while research has identified solar and lunar influences on behavioral patterns in some species, few studies describe these effects on white-tailed deer. Our goal was to determine if solunar charts can predict periods of increased activity in white-tailed deer. Thirty-eight adult male, white-tailed deer were equipped with GPS collars programmed to collect locations every 30 minutes from August-December during 2010-2012. Deer were classified as active or inactive between consecutive GPS fixes based upon a 38.44 meter threshold for total distance moved. We used logistic regression to model the odds of activity dependent on solunar events. On days furthest from the full or new moon, deer were less likely to be active during moonrise and moonset periods, and more likely to be active during moon overhead and moon underfoot periods, than during surrounding times. On days with greater proximity to the new or full moon the probability of activity during moonrise and moonset periods increased from 0.429 to 0.660 and 0.464 to 0.652, respectively, while decreasing during moon overhead and moon underfoot periods from 0.597 to 0.467 and 0.576 to 0.364, respectively. These data suggest events identified by solunar charts have some association with deer activity. However, the relationships between lunar events and lunar phase expressed in solunar charts may be misleading.

Jordan S. Nanney, Craig A. Harper, David A. Buehler, Gary E. Bates – University of Tennessee

Closed-canopy forests dominate the landscape in many parts of the eastern United States and often lack a well-developed forest understory, which limits nutrition available for cervids. We evaluated the influence of timber harvest combined with prescribed fire and/or herbicide treatments in mixed-hardwood stands on forage availability for elk (Cervus elaphus) and white-tailed deer (Odocoileus virginianus), July-August 2013 and 2014, in east Tennessee. We compared forage availability in closed-canopy mature forest (MATFOR) and 6 timber harvest treatments (timber harvest alone (HARV), early-growing season fire (EBURN), late-growing season fire (LBURN), herbicide alone (HERB), herbicide and early-growing season fire (EB_HERB), and herbicide and late-growing season fire (LB_HERB)). Forage was measured by collecting leaf material of herbaceous and woody plant species considered selected by elk or deer in the literature. Forage availability in MATFOR (133 kg/ha : 118 lb/ac) was less than all timber harvest treatments. More forage was available in HARV (1,276 kg/ha : 1,139 lb/ac), EBURN (1,135 kg/ha : 1,013 lb/ac), LBURN (1,321 kg/ha : 1,178 lb/ac), and HERB (1,151 kg/ha : 1,127 lb/ac) than EB_HERB (814 kg/ha : 726 lb/ac) and LB_HERB (893 kg/ha : 797 lb/ac). Additionally, we compared vegetation composition among timber harvest treatments. Herbaceous species coverage did not differ (P = 0.062); although woody species coverage did differ among treatments (P = 0.0124). Woody species coverage in LB_HERB (17%) was less than HARV (50%), EBURN (46%), and LBURN (41%), but similar to EB_HERB (28%) and HERB (32%). Combining herbicide and prescribed fire following timber harvest appears to be an effective technique to increase forage for cervids and facilitate the transition of young forest to early successional plant communities in the eastern United States.

S. Kathryn Hasapes, Christopher E. Comer – Austin State University

Despite decades of interest and research, many questions remain about seasonal movements and habitat use of white-tailed deer (Odocoileus virginianus), particularly in the Southeast. The advent of GPS-based telemetry has made detailed studies of year-round movements feasible. We assessed monthly habitat use using compositional analysis for adult male (n = 15) and female (n = 15) deer at Barksdale Air Force Base in northwestern Louisiana using GPS radiocollars collecting locations at hourly intervals over approximately one year. Males had larger monthly home ranges (97-380 ha) than females (44-181 ha), particularly in fall and winter; however, habitat use was similar between sexes. Early-successional habitats, such as shrub communities, were used preferentially by both sexes throughout the year, as were mature bottomland hardwood stands. Thinned hardwood stand and wetland habitats were used less than expected. Food plots and fields were used preferentially when they were small and widely dispersed on the landscape but large openings were avoided. Our results suggested that deer of both sexes were able to obtain resources to support their year-round needs in a seasonally consistent, relatively small area and that management to benefit deer at the site has been generally successful in producing high quality habitat.

Taylor N. Simoneaux, Bradley S. Cohen, Elizabeth A. Cooney, Rebecca M. Shuman, Michael J. Chamberlain, Karl V. Miller –University of Georgia

Understanding movement patterns of adult male white-tailed deer (Odocoileus virginianus) is critical to explaining population dynamics, predation interactions, gene flow, and disease spread of this demographic. Relatively few studies have investigated movement ecology of mature male deer, although recent trends in hunter-harvest selectivity have led to an increased representation of this cohort in many herds. Multiple co-occurring variables influence spatiotemporal variation in deer movements, but individuals should move at an optimum rate to maximize individual health and fitness while minimizing high-risk encounters. We used GPS telemetry data from 24 adult male deer (≥ 2.5 years old) in northeastern Louisiana to determine fine-scale movement patterns during the 2013-2014 and 2014-2015 hunting seasons. We calculated half-hour step lengths and performed generalized linear mixed models to examine the effects of habitat, age, breeding chronology, photoperiod, and refugia from hunting on step length. We used information-theoretic approaches to identify the most parsimonious model. On average, older individuals moved less and deer moved more in agriculture and mature hardwood areas. Movements were greatest during the rut, especially at crepuscular and night hours. Our most parsimonious model predicted mature males tended to be more crepuscular in refuge areas where they were infrequently hunted compared to adjacent lands which were open to hunters the entirety of the season. Mature males seem to modify movements to avoid hunter predation, particularly if predation risk is chronic. Decreased disturbance from hunting may prevent deer from developing related-antipredator behaviors, thereby facilitating successful harvest of these animals upon initiation of hunting.