The U.S. National Park Service has started the process of introducing more wolves onto Isle Royale on Lake Superior, but it's come with a casualty.
The NPS said it successfully captured four wolves from the Grand Portage Indian Reservation in northeastern Minnesota on Tuesday, of which two adult gray wolves – a 4-year-old female and a 5-year-old male – were released into Isle Royale National Park.
The two others were released as they didn't meet the age threshold.
However, things didn't go so well for another female wolf that was captured on Thursday and deemed fit to be moved to Isle Royale.
The wolf was sedated and taken to a holding facility for further examination, but while in holding its condition deteriorated, and it died despite the efforts of veterinarians.
It's been taken to the University of Minnesota's Veterinary Diagnostic Lab for study.
Since the wolf's death, the NPS has changed its sedation procedures "to lower stress during transportation" as well as adjusting the length of time it's held before being transported.
The NPS intends to introduce 20-30 wolves over the next 5 years to Isle Royale.
The island used to have a wolf population of around 50 in the 1980s, but they were descended from a small pack and inbreeding led to plummeting numbers to the point that only two remain today.
Meanwhile the population of their prey, the moose, has tripled over the last decade to around 1,500, thanks to the decline of the predator.