William Severud

Degree Type

PhD

Degree Program

Wildlife Ecology and Management

Project

Assessing Calf Survival and the Quantitative Impact of Reproductive Success on the Declining Moose (Alces americanus) Population in Northeastern Minnesota

Position

Research Assistant

Support

Minnesota Department of Natural Resources, Doctoral Dissertation Fellowship

Project Abstract

Neonatal survival and recruitment are important drivers of population growth.  The moose (Alces americanus) population in northeastern Minnesota has declined ~55% from 2006 to 2016.  Survival patterns and specific causes of mortality of calves were largely unknown in this study area.  We placed GPS collars on neonatal moose in 2013 and 2014 to estimate survival, cause-specific mortality, and space use of calves and their mothers.  Due to an executive order we were precluded from collaring in 2015.  Using an alternate method involving behavioral cues from already collared moose and helicopter surveys, we continued the study. Survival of calves dropped precipitously to 58% by 30 days of age in 2013 and 2014, and then to 34% by 9 months of age.  Median age of death of calves that died before 1 year of age was 17.5 days.  Hazard started low at birth and spiked at ~20 days old.  Similar patterns were seen in 2015, with a 30-day survival rate of 63% and 10-month survival rate of 40.5%.  Over-winter survival was generally high in all 3 years.  We will model population trajectory using our observed demographic rates and those from the companion adult moose mortality project.  Predation was the leading cause of calf mortality in 2013 and 2014, with 84% of mortalities due to wolves (Canis lupus) or black bears (Ursus americanus).  Predation was an important cause of mortality in 2015 as well, but the relative certainty in assigning cause was low.  Calves were generally preyed upon once the dam and calves departed their calving sites.  Wolf predation was the leading cause of calf mortality in our study.  We will also examine fine scale habitat factors (hiding cover, forage availability, canopy closure, etc.) at calving sites, peak lactation sites, and mortality sites.  Identifying specific causes of calf mortality and understanding their relations to various landscape characteristics and other extrinsic factors should yield insight into mechanisms contributing to the declining moose population in northeastern Minnesota and serve as a basis for an ecologically sound management response. 

Publications

DelGiudice, G. D., and W. J. Severud. 2016. Blood profiles and associated birth characteristics of free-ranging moose (Alces americanus) neonates in a declining population in northeastern Minnesota.  Alces 52: In press.
Severud, W. J., G. D. DelGiudice, and T. R. Obermoller. 2016. Minimizing mortality of moose neonates from capture-induced abandonment. Alces 52: In press.
Severud, W. J., and G. D. DelGiudice. 2016. Potential vertical transmission of winter ticks (Dermacentor albipictus) from moose (Alces americanus) dams to neonates. Journal of Wildlife Diseases 52:186-188.
Severud, W. J., G. D. DelGiudice, T. R. Obermoller, T. A. Enright, R. G. Wright, and J. D. Forester. 2015. Using GPS collars to determine parturition and cause-specific mortality of moose calves. Wildlife Society Bulletin 39:616-625.
DelGiudice, G. D., W. J. Severud, T. R. Obermoller, R. G. Wright, T. A. Enright, and V. St-Louis.  2015. Monitoring movement behavior enhances recognition and understanding of capture-induced abandonment of moose neonates.  Journal of Mammalogy 96:1005-1016.

MNDNR Reports

Severud, W. J., G. D. DelGiudice, T. R. Obermoller, R. J. Ryan, and B. D. Smith. 2015. An alternate method to determine moose calving and cause-specific mortality of calves in northeastern Minnesota. Pages 93–108 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2014. Minnesota Department of Natural Resources, St. Paul, USA.
DelGiudice, G. D., and W. J. Severud. 2015. Blood profiles and associated birth characteristics of free-ranging moose (Alces americanus) neonates in a declining population in northeastern Minnesota, 2013. Pages 109–122 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2014. Minnesota Department of Natural Resources, St. Paul, USA.
DelGiudice, G. D., and W. J. Severud. 2015. Assessing winter nutritional restriction of moose and its relation to population dynamics in northeastern Minnesota, winter 2013–2015.  Pages 123–136 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2014. Minnesota Department of Natural Resources, St. Paul, USA.
DelGiudice, G. D., W. J. Severud, T. R. Obermoller, K. J. Foshay, and R. G. Wright. 2014. Determining an effective approach for capturing newborn moose calves and minimizing capture-related abandonment in northeastern Minnesota. Pages 25–39 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2013. Minnesota Department of Natural Resources, St. Paul, USA.
Severud, W. J., G. D. DelGiudice, T. R. Obermoller, K. J. Foshay, and R. G. Wright. 2014. Using GPS collars to determine moose calving and cause-specific mortality of calves in northeastern Minnesota: progress report on second field season. Pages 40–56 in Cornicelli, Lou, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2013. Minnesota Department of Natural Resources, St. Paul, USA.
DelGiudice, G. D., E. Butler, M. Carstensen, and W. J. Severud. 2013. Assessing nutritional restriction of moose in northeastern Minnesota, winter 2013: a pilot. Pages 63–73 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2012. Minnesota Department of Natural Resources, St. Paul, USA.
DelGiudice, G. D., W. J. Severud, and R. G. Wright. 2013. Helicopter capture of newborn moose calves in northeastern Minnesota: An evaluation. Pages 40–51 in Cornicelli, Lou, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2012. Department of Natural Resources, St. Paul, USA.
Severud, W. J., G. D. DelGiudice, and R. G. Wright. 2013. Evaluating the use of GPS-collars to determine moose calving and calf mortalities in northeastern Minnesota. Pages 52–62 in L. Cornicelli, M. Carstensen, M. D. Grund, M. A. Larson, and J. S. Lawrence, editors. Summaries of Wildlife Research Findings 2012. Minnesota Department of Natural Resources, St. Paul, USA.
William Severud