Michigan's Isle Royale National Park is down to its last three wolves, predictably representing a sharp decline from the previous winter.

In their annual Winter Study, researchers from Michigan Technological University (MTU) also estimated the population of moose, wolves' primary prey on the island, to be 1,250. The moose population is seemingly on the rise while the wolves are in decline.

"It's not the presence of wolves that matters so much, it's whether wolves are performing their ecological function," study lead author John Vucetich, an associate professor of wildlife ecology at MTU, said in a press release. "There is now a good chance that it is too late to conduct genetic rescue."

The researchers said the wolf group is made up of two adults and a pup aged nine months who is apparently not healthy. The Winter Study has observed an uptick in inbreeding among the Isle Royale wolves as their numbers decreased.

The researchers also observed two wolves that were visitors on the island, apparently reaching it on a natural ice bridge that connects it to the mainland in the winter. Vucetich and MTU research professor Rolf Peterson say visiting wolves could potentially be a good sign, but these ones apparently did not notice the three-member pack.

"One must use the word, 'naturally', carefully these days," Peterson said in the release, addressing the possibility of letting the situation play out without human intervention. "The human imprint is written all over the dynamics of this wolf population in recent decades."

Making matters worse for the wolves is their prey now vastly outnumber them; another factor for the researchers to consider.

"At that time the moose population had considerable impact on forest vegetation," Vucetich and Peterson wrote in the study. "Concerns remain that the upcoming increase in moose abundance will result in long-term damage to the health of Isle Royale's vegetative community."