CHICAGO — The wolf was believed to be a lone male expelled by a pack in Wisconsin. The hunter who shot him in northwestern Illinois, allegedly keeping his skull as a trophy, was the first person in the state ever prosecuted for shooting a wolf under federal endangered species laws.
The incident, resolved in 2013 when the hunter pleaded guilty and paid a $2,500 fine, comes amid evidence of a modest but perceptible uptick in the number of wolves roaming across the Wisconsin border into heavily populated and widely farmed Illinois.
Illinois’ own once-thriving wolves were hunted to extinction by the 1860s. But since the first confirmed sighting in the state in 150 years, in 2002, wolf sightings have gone from rare to regular — with at least five in the last three years.
‘‘We used to joke with our counterparts in Wisconsin that, ‘Yeah, one day your wolves will be coming to Illinois,’ ’’ said Joe Kath, the endangered species manager at Illinois’ Department of Natural Resources. ‘‘Well, we’ve reached that day.’’
That has state wildlife officials contemplating another day — still way off — when there are so many wolves in Illinois they’ll have to ask residents to decide if they want to encourage the growth of a wolf population or strictly limit it, possibly through hunting or trapping.
The North American wolves, known as gray or timber wolves, have proven resilient.
Their numbers in the lower 48 states fell to a few dozen by 1970 but dramatically rebounded with federal protections and wildly successful reintroduction programs in Minnesota, Wisconsin, Michigan, Montana, Idaho, Oregon, Washington, and Wyoming.
In Wisconsin, which shares a 150-mile border with Illinois, wolf numbers went from few to none in the 1970s to more than 800 today.
The core of Wisconsin’s wolf population is in its forested north. But, explained Kath, of their own accord, the wolves have moved south. There’s even one pack near Beloit, Wis., only miles from Illinois.
Several shootings of wolves have occurred in JoDaviess County, which hugs the Wisconsin border in Northwestern Illinois. That’s where Earl Sirchia of Elgin killed the wolf that drew the scrutiny of federal prosecutors.
Sirchia, who had faced a maximum one-year prison sentence, pleaded guilty months before his trial in Chicago was set to start. He was accused of taking the wolf’s skull, and he allegedly had a photograph taken of himself with the dead wolf — a picture investigators later used in evidence, said Timothy Chapman, the assistant US attorney in Chicago who handled Sirchia’s case.