21st-Century Foxes

Mueller Time

“I’ve always been interested in urban wildlife,” Mueller says. A Wisconsin native, he did his undergraduate work at UW–Stevens Point, where he studied wildlife ecology, but much of his focus had been on whitetail deer. Deer are important animals in a state where deer hunting is a billion-dollar industry. But whitetails have been heavily studied. Canids offered Mueller the opportunity for “a ton of growth.”

With the Urban Canid Project, Drake designed the program, and Mueller provided time — a lot of hours spent doing the project’s labor. The result has been one of Madison’s most intensive studies of local predators.

The two ecologists sketched out a core research area that extends from Lake Mendota in the north to the Arboretum in the south, from Madison’s Beltline Highway in the west to the isthmus in the east. “Of course,” says Drake, “the dad-gum animals go where they want. The boundaries were our research area, but we tried to follow them wherever they went.”

Snag and Tag

Winter is trapping season. From November through March, the Urban Canid Project watches for snowfall to find the nights when it might set its traps. Coyotes are nocturnal — they do their wandering at night. Foxes are crepuscular — they’re active in the twilight hours at dusk and dawn. Both are shy of humans, so the key is snow, which shows the animals’ tracks: coyotes and foxes tend to follow the same paths, so spotting their tracks in the snow shows the Urban Canid team where to set their traps.vixen

The traps themselves are cable restraints, which are a bit like choke chains. According to Drake, the project has had more than 5,500 trap nights — the number of traps multiplied by the number of nights each trap is in the field. The goal has been to trap at least one coyote per active pack in Madison and one fox per family. This gives Drake and Mueller an idea of range, territory, and social structure.

Working with between 20 and 30 undergraduates and as many veterinary students as they can convince to volunteer their time, Drake and Mueller began to track, trap, and document the foxes and coyotes that live in their research zone. Each animal would get a quick medical exam — weight and vitals, blood sample, and a swab of the nose and rectum — and then receive colored ear tags and a radio collar so that Drake and Mueller could follow their wanderings.

Radio collars would not be Drake’s first choice. He’d prefer GPS trackers, which would enable him to follow each animal at any time of day or night, all from his laptop computer. But GPS is expensive. Each radio collar costs only $220. A GPS tracker would cost $1,500 to purchase and then $500 a year to operate. “That’s a lot of money,” Drake says.

So radio collars it was, and it was Mueller’s job was to use telemetry to track the collared animals. Working five-hour shifts, he’d drive around Madison, spending an hour or so in each area where he hoped to find a fox or coyote. Because he wasn’t able to track the animals around the clock, he rotated his shifts so that he would, over time, cover all hours of the day and night to see where the animals went and when they were on the move.

To help cover the rest of the time, Drake and Mueller leveraged the animals’ ear tags, which help to expand the Urban Canid tracking team. Each animal’s tags are a unique color combination, and Drake uses social media and a citizen-science reporting portal called iNaturalist.org to encourage Madisonians to report fox and coyote sightings, and when applicable, ear-tag color. Thus, about 800 people around the city have made about 1,200 reports, helping to expand the dataset on the animals’ travels.

“We’ll publish a paper overlapping the radio-location data with iNaturalist data,” Drake says. “We’ll show that fox and coyote share the same territory about 65 percent of the time.”

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