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Animals commonly form groups with conspecifics. Hypotheses on the drivers of group size often (but not always) pertain to fear of predation and food availability or quality. However, for a more complete understanding of group forming, multiple, possibly interacting mechanisms should be considered. We used camera traps, detectability estimates from distance sampling, and hierarchical Bayesian modeling to index group size and test multiple additive and interacting group‐formation hypotheses in white‐tailed deer (Odocoileus virginianus), within Indiana, USA. We found a strong relationship between our index of group size and (1) a three‐way interaction between spatiotemporal pulses in fear of natural predation risk and anthropogenic development and (2) a three‐way interaction between the local cover (defined as the amount of vegetative cover in the immediate area of the camera), the area of concealment (defined as forests or wetlands) within the larger landscape, and time of day. Specifically, we documented larger groups in areas near anthropogenic development, in areas with high predator use intensity, and when predators were active. Additionally, we found larger groups during dawn and dusk when deer were most active in locations with sparse local cover when the area of concealment in the surrounding landscape was small, and within dense local cover when the area of concealment in the surrounding landscape was large. Our methods can aid future behavioral and ecological studies, as we present a clear and easily replicable strategy that infers group membership from spatiotemporal proximity, corrects for differences in detectability, and enables sampling across large spatial and long temporal scales. Our findings indicate that fear of natural predators and anthropogenic disturbance interactively explain variation in group size. [ABSTRACT FROM AUTHOR]

Aerial vehicles equipped with infrared thermal sensors facilitate quick density estimates of wildlife, but detection error can arise from the thermal sensor and viewer of the infrared video. We reviewed published research to determine how commonly these sources of error have been assessed in studies using infrared video from aerial platforms to sample wildlife. The number of annual articles pertaining to aerial sampling using infrared thermography has increased drastically since 2018, but past studies inconsistently assessed sources of imperfect detection. We illustrate the importance of accounting for some of these types of error in a case study on white‐tailed deer Odocoileus virginianus in Indiana, USA, using a simple double‐observer approach. In our case study, we found evidence of false negatives associated with the viewer of infrared video. Additionally, we found that concordance between the detections of two viewers increased when using a red‐green‐blue camera paired with the infrared thermal sensor, when altitude decreased and when more stringent criteria were used to classify thermal signatures as deer. We encourage future managers and ecologists recording infrared video from aerial platforms to use double‐observer methods to account for viewer‐induced false negatives when video is manually viewed by humans. We also recommend combining infrared video with red‐green‐blue video to reduce false positives, applying stringent verification standards to detections in infrared and red‐green‐blue video and collecting data at lower altitudes over snow when needed. [ABSTRACT FROM AUTHOR]

Information on agkistrodon piscivorus is presented which include informations related to topics like its diet, the habitat in which it is found, and its physical traits.

The article reports a case of predation on Agkistrodon piscivorus (Northern Cottonmouth) by a Coyote (Canis latrans), marking the first detailed observation of such an event.