This study provides evidence that wolverines are rare in the southern Madison Range of southwestern Montana, and that mortality due to trapping may be a significant limiting factor.

Excerpts
"On the Madison Range Study Area (MRSA), we constructed eight new wolverine traps. Seven traps were open for a total of 428 trap-nights, during which time six wolverine visits occurred (likely by two to three individuals). One sub-adult female was captured two times, resulting in a low capture rate of one wolverine capture per 214 trap-nights. Approximately three weeks after her capture, F102 was harvested by a recreational fur trapper, two days before the close of the furbearer trapping season. Two additional wolverines, an adult male and a sub-adult female, were harvested within the MRSA this year prior to our traps being opened..."
(Executive Summary)

"Winter Capture Effort.—We constructed eight log box-traps for wolverine capture. We operated our wolverine trap-line from the second week of January through the third week of March. Although we had constructed eight traps, only seven were opened due to logistical constraints. Seven traps were open for a total of 428 trap-nights, during which time six wolverine visits occurred (likely by two to three individuals). Two of the seven trap sites were visited by wolverines. These two sites were two of the three sites that were visited by wolverines during the previous winter’s preliminary season. One sub-adult female wolverine, F102, was captured and handled on two occasions. F102 was initially captured in late January in an area that receives heavy use by snowmobiles. Approximately three weeks after her capture she was harvested by a recreational fur trapper, two days before the close of the furbearer trapping season. Poor weather conditions resulted in only one aerial telemetry location for this wolverine. One pine marten (Martes americana) and eight red fox (Vulpes vulpes) were incidentally captured and then released. Wolverine capture rate was low on the MRSA, one wolverine per 214 trap-nights." (p. 8)

"Wolverine Harvest.--Two additional wolverines were harvested from within the MRSA this year. The furbearer season opens December 1 and closes February 15. Both wolverines were taken in December prior to our traps being opened. The first was a 32 lb. adult male and the second was a sub-adult female taken in a drainage where we later opened two traps; F102 was later harvested in this same drainage. Nine wolverines were harvested in Region 3 (southwestern Montana) this winter, an unusually high number (typically 0-2)." (p. 8)