Date of this Version
Brewer, S. 2021. Spatiotemporal interactions between deer and cattle. Undergraduate Honors Thesis, University of Nebraska-Lincoln, Lincoln, NE, USA.
Mule deer, white-tailed deer, and cattle are sympatric on the landscape throughout many portions of Nebraska and encounter each other in time and space. By considering variation in daily activity patterns and non-random patterns in the timing of passage through specific locations, we can better understand whether animals may be avoiding each other temporally when sharing space. I investigated temporal activity patterns and avoidance/attraction ratios to investigate if deer altered their activity patterns in the presence of cattle and if they exhibited avoidance at a study site near McCook, Nebraska, USA. We collected data from 19 game cameras that were deployed for approximately five months and investigated overlap in activity patterns between deer and cattle when both were present at a given location. To investigate if deer avoided cattle, we estimated avoidance/attraction ratios by documenting the time between detecting them at specific camera trap locations. We recorded 2033 total detections of deer and cattle. Deer did not significantly alter their activity patterns relative to whether cattle were present or absent with overlap coefficients between deer and cattle ranging from 0.68-0.90. Deer were primarily crepuscular while cattle were diurnal. For the avoidance/attraction ratios, we recorded 1355 observations of mule deer or cattle, whereas we did not detect white-tailed deer frequently enough to include in the analysis. The mean ratios across cameras for all adult mule deer, adult female mule deer, and adult male mule deer ranged from 1.1-2.3 (ratios > 1 indicate avoidance). Thus, deer exhibited some avoidance of cattle but only significantly for the analysis will all adult mule deer pooled. Our results may suggest that deer and cattle exhibit relatively little competition in southwestern Nebraska other than for space. Overall, deer did not exhibit strong temporal avoidance of cattle, but deer did appear to avoid areas when cattle are present. Future studies should increase the length of the study and number of cameras to maximize the number of observations. Additional research should also include spatial occupancy to evaluate how these species are distributed spatially on the landscape and compare these relationships in different locations where grazing varies to provide additional insight into interactions between deer and cattle in shared agricultural landscapes. Understanding the influence of cattle on deer can help to ensure that cattle production and deer harvest are maximized.