Caught on Camera! River Otter Snapped for First Time in 15 Years of Monitoring by Lincoln Park Zoo’s Wildlife Cams

River otter snapped this fall in Lincolnshire by a wildlife camera set up by Lincoln Park Zoo’s Urban Wildlife Institute. (Courtesy Lincoln Park Zoo)River otter snapped this fall in Lincolnshire by a wildlife camera set up by Lincoln Park Zoo’s Urban Wildlife Institute. (Courtesy Lincoln Park Zoo)

With wildlife cameras set up at more than 100 sites within a 30-mile radius of Chicago, Lincoln Park Zoo’s Urban Wildlife Institute has captured hundreds of thousands of images of critters since it launched a monitoring project in 2010.

That’s a lot of snapshots of deer, squirrels, skunks, rabbits, coyotes, minks, the occasional weasel and even, memorably, a hawk in mid-swoop.

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“We want to know what’s here,” which in turn guides conservation recommendations, said Seth Magle, director of the Urban Wildlife Institute.

Well, look who just showed up: a North American river otter.

After more than a few false IDs and several tantalizing random hints of an otter-like shoulder or tail, one of the zoo’s cameras finally clicked at the right moment and, for the first time in nearly 15 years, caught an otter in full view. Twice.

Staff spotted the photos of the elusive otter during a quick initial scroll through image files collected during the institute’s fall monitoring “season” — one of four conducted annually in January, April, July and October.

“We knew (otters) were in the area, but they stick to water and our cameras are on land,” Magle said. “When we saw these two pictures, it was really exciting.”

This confirmed sighting — at a golf club in suburban Lincolnshire, near the Des Plaines River — is the latest chapter in the river otter’s amazing recovery story.

Otters are often confused with beavers and muskrats. Otters are the far superior swimmers, built for speed. Their small ears don’t protrude so as to decrease drag in the water. (Andreas Schantl / Unsplash)Otters are often confused with beavers and muskrats. Otters are the far superior swimmers, built for speed. Their small ears don’t protrude so as to decrease drag in the water. (Andreas Schantl / Unsplash)

River otters (Lontra canadensis) were hunted to near-extinction in parts of the Midwest, killed for their pelts. By 1989, wildlife officials estimated only 100 of the creatures were left in Illinois.

In the 1990s, the Illinois Department of Natural Resources relocated 346 river otters from Louisiana and Kentucky, setting them loose at 15 sites along the Illinois, Kaskaskia and Wabash river basins. The otters thrived, to the point they’re no longer even considered threatened.

Still, Chicago is 150 miles from the nearest place where otters were reintroduced in Illinois. The fact that they’ve ventured so far into urban territory is a testament to the health of the region’s rivers.

“It wasn’t that long ago that our waterways were a joke,” Magle said. “A lot of organizations are doing amazing work.... The improvement of water quality is a big story.”

Not only are area rivers now clean enough to support the large fish populations otters need to sustain themselves, but the push to restore natural river banks has added favorable habitat.

“We’ve done so much to green our city, and now we get this suite of species,” Magle said.

By now, river otters have been confirmed in every one of the region’s watersheds. But while their presence has been well documented, how they’re moving through and using the landscape remains a mystery — a mystery the Forest Preserve District of Cook County is helping to solve.

A camera trap at Crab Orchard National Wildlife Refuge in Southern Illinois caught this otter performing a classic belly slide in 2014. (U.S. Fish and Wildlife Service)A camera trap at Crab Orchard National Wildlife Refuge in Southern Illinois caught this otter performing a classic belly slide in 2014. (U.S. Fish and Wildlife Service)

The district is a partner in a study — entering its third year — into urban otter behavior, similar to the district’s long-running urban coyote study, which is still going strong at 24 years and counting.

“Here’s an apex predator in our wetlands that has not been present in over 100 years, that has re-inserted itself amongst us,” Chris Anchor, wildlife biologist with Cook County forest preserves, said of otters. “Now you want to ask questions like how is it going to affect the rest of the biodiversity that’s already found in the area? What diseases can it carry?”

Other unknowns, Anchor said, include the size of the population, how far individuals move to expand their territories, and how many pups survive to adulthood (what’s known as a recruitment rate).

Some areas in the region, particular around Palos along the Des Plaines River, seem to have a steady, relatively constant population of otters. Almost everywhere else, otters’ presence is intermittent.

“It seems like the animals move in, they may have a litter, and then they seem to leave, and we don’t understand why,” Anchor said.

Where the zoo’s monitoring is largely passive, relying as it does on a network of cameras to record observations of the region’s wildlife, the forest preserve’s project involves active tracking through the use of radio telemetry, a process that has its detractors.

“We get criticized for that because it’s invasive, we actually have to handle the animal,” Anchor said. “But the foundation for all our work is disease surveillance and disease movement across the landscape. And there’s no way you could study that unless you actually handled the animal.”

To date, 11 otters have been captured and outfitted with transmitters, with assistance from veterinary pros at Brookfield Zoo, who also conduct health assessments while the animal is in hand.

“You put a transmitter on it and you follow it. You find out what they’re actually doing. Otherwise it’s just an opinion, it’s not fact,” said Anchor. “That’s a huge chasm to cross if you want to understand disease epidemiology.”

River otters love to eat fish, consuming two to three pounds a day. (Tom Koerner / U.S. Fish and Wildlife Service)River otters love to eat fish, consuming two to three pounds a day. (Tom Koerner / U.S. Fish and Wildlife Service)

Those transmitters have already revealed some interesting behavior that contradicted everything Anchor had been led to believe about river otters.

All of the available scientific literature on the animal — conducted, he noted, in rural areas — indicated that otters move via waterways or wetlands. Yet Anchor found otters hanging out in isolated ponds in the middle of a town, having traveled miles.

“They’re actually moving over land. And they’re doing this successfully,” he said. “Here they’re actually exploiting opportunities that are relatively far removed from any waterway and we didn’t think that they would be able to navigate moving through villages. And it’s quite obvious that they can.... We didn’t know they were capable of that, which is amazing to us.”

How do the otters home in on those isolated ponds? That’s anyone’s guess.

“What we have found over the years, is that the more information you glean from this work, the more questions you’re able to ask," Anchor said. “Because you have more information to build a foundation of understanding, and once you have that foundation, now you can start asking questions that you never even conceived of when you started the study.”

One thing Anchor, like Magle, is certain of, is that having river otters in the Chicago region is a good thing.

“We’re the third largest metropolitan area in North America, and to actually be gaining new species is huge,” Anchor said. “Most people feel that an increase in biodiversity equates with an increase in overall environmental health. And this is the environment that we all have to share.”

Lincoln Park Zoo Needs You to Help ID Wildlife

In a perfect world, Seth Magle said he’d have his wildlife cameras out in the field 365 days a year, gathering not just still photos, but video. Maybe then he’d have a fuller picture (no pun intended) of why animals like gray foxes, which used to be snapped routinely, rarely if ever show up anymore.

But who would comb through all that footage? As it is, having cameras operational four months of the year produces more data than staff at the wildlife institute can process.

The wildlife institute is just beginning to use artificial intelligence to help sift through the tens of thousands of images collected every season.

At the moment, though, volunteers with Chicago Wildlife Watch are performing the lion’s share of identifications.

“Without help, it would be impossible to keep up,” Magle said. “It is an enormous undertaking.”

Click here for more information about Chicago Wildlife Watch.

Photo credit: A second image of the river otter. (Courtesy Lincoln Park Zoo)

Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]


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