Evaluating Success for a Within-Mountain Range Transplant of Bighorn Sheep in Southwestern Montana

Abstract

Montana Fish, Wildlife and Parks (MFWP) performed a bighorn sheep (Ovis canadensis) transplant within the Madison Mountains of southwest Montana February 2015.  Once with 5 distinct wintering ranges, the herd since endured, and recovered from, several all-age die-offs.    As of 2013, one historic wintering area was overpopulated (>250 bighorn), one sparsely populated (~30 bighorn), and three historic wintering areas were left unoccupied: Indian Creek, Wolf Creek, and the Henry’s Mountains.  MFWP evaluated habitat and proposed to reintroduce bighorn from the overpopulated wintering range to either Wolf Creek or Indian Creek.  After the EA and public process concluded, Wolf Creek was the selected release site.  MFWP captured 52 bighorn from the overpopulated winter range using a drop-net, and moved them via trailer to the release site.  Ten of the released bighorns were fitted with LOTEK Lifecycle GPS collars, providing satellite location data once daily for up to 4 years.  Transplant success was mixed, with three collared bighorns immediately returning to their former range, three collared bighorns wintering at the sparsely populated intermediate range, and four collared bighorns remaining through winter and into summer at the reintroduction site.  One bighorn died shortly after release.  The four collared bighorns remaining at the release site explored Indian Creek through summer, then in July, 3 returned to their original range and 1 remained in the transplant area.  Of the 52 bighorns transplanted, approximately 10-15 remain in the Wolf Creek transplant range.  Subsequent transplants are planned to enhance the restoration of bighorn sheep in the Madison Range.