Annual Pronghorn Survival of a Partially Migratory Population

Paul F. Jones, Andrew F. Jakes, Daniel R. Eacker, Mark Hebblewhite

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The importance of conserving migratory populations is recognized across a variety of ungulate taxa, yet the demographic benefits of migration remain uncertain for ungulate populations that exhibit partial migration. We hypothesized that migratory pronghorn (Antilocapra americana) would experience greater survival compared to residents by moving longer distances to avoid severe winter weather and access higher quality forage. We used a Bayesian time-to-event approach to analyze the fates of 175 radio-collared adult female pronghorn monitored over 8 biological years (2004–2011) in the Northern Sagebrush Steppe ecosystem. Annual survivorship of migratory pronghorn was 7% higher on average compared to residents but not statistically different. Migratory pronghorn had higher survivorship in summer and winter compared to residents, and few mortalities were observed during the short autumn and spring migration periods. Mortality risk for both movement tactics intensified under more severe winter weather; winter weather severity alone best explained annual pronghorn mortality risk. The top model predicted survival rates to decline on average by 56% over the range of observed winter climatic conditions. To minimize human impacts to pronghorn during extreme climatic events, we recommend working with transportation departments and land managers to enhance pronghorn crossings of roads and railroads, and landholders to modify fences to wildlife-friendly standards.

Original languageEnglish
Pages (from-to)1114-1126
Number of pages13
JournalJournal of Wildlife Management
Volume84
Issue number6
DOIs
StatePublished - Aug 1 2020

Keywords

  • Alberta
  • Antilocapra americana
  • Bayesian
  • Montana
  • Saskatchewan
  • adult female survival
  • movement tactics
  • pronghorn
  • winter severity

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