Maternal Behavior Indicates Survival and Cause‐Specific Mortality of Moose Calves

• Published in: The Journal of Wildlife Management
• Main Authors: Obermoller, Tyler R., Delgiudice, Glenn D., Severud, William J.
• Other Authors: Minnesota Environmental and Natural Resources Trust Fund, Wildlife Restoration (Pittman-Robertson) Program, MNDNR Section of Wildlife's Wildlife Populations and Research Unit
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: Alces alces; Canis lupus
• Online Access: http://dx.doi.org/10.1002/jwmg.21658; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjwmg.21658; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jwmg.21658; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jwmg.21658

ABSTRACT Continuing research on cause‐specific mortality and annual survival of moose ( Alces alces ) calves in northeastern Minnesota, USA, is important to understanding the long‐term trajectory of the population. In 2013 and 2014, we observed global positioning system (GPS)‐collared, female moose exhibit a specific behavior (i.e., mortality movement) associated with the death of their GPS‐collared neonate. The females made a rapid, long‐distance movement (flee), followed by a return to the calf mortality site. We used characteristics of this movement in 2013–2014 ( n = 46) to develop models for assessing calf survival, and then evaluated these models using female movement rates ( n = 49) in 2015−2016. Using this behavior as an indicator of calf mortality in 2016, we conducted field investigations, leading to evidence of 15 mortalities at a mean age of 30.6 ± 15.5 (SE) days (range = 3–243 days). We launched 21 investigations in response to a mortality movement and they resulted in confirmation of 11 of the 15 calf mortalities. Specific causes of mortality included 9 wolf ( Canis lupus )‐kills, 3 black bear ( Ursus americanus )‐kills, 1 unknown predator‐kill, and 2 deaths following vehicle collisions. The mean distance females fled after a mortality was 1,873 ± 412 m (range = 126–5,805 m, n = 14). Females that made return visits returned a mean 2.8 ± 0.5 times (range = 1–5, n = 8) to within a mean 106 ± 22 m (range = 34–230 m, n = 8) of the mortality site. Calf survival to 30 days of age was 67 ± 8% (95% CI = 53–84%, n = 36) but declined to 53 ± 8% (95% CI = 39–72%, n = 36) by 3 months of age. We developed 2 population‐level movement models to improve the efficacy of using the mortality movement to identify and locate calf mortalities in real time via field investigations. The first approach, a temporal‐based model, used a 3‐day average movement velocity threshold (118 m/hr) for all females to indicate calf mortality and accurately predicted survival status in 51% ( n = 105) of the cases. The second approach, an ...