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How will coyotes respond when food sources dry up?

5-26-10  At Poplar Creek Forest Preserve   Cook County forest preserve district biologists take careful datcaptured 3 pups

5-26-10 At Poplar Creek Forest Preserve , Cook County forest preserve district biologists take careful data on the captured 3 pups before releasing them back to their den. The 3 coyoite pups ... two were female and one was male. sun-times photo by al podgorski

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Updated: February 3, 2013 6:16AM

A mysterious virus that killed hundreds of white-tailed deer in parts of Cook County means coyotes there are heading into winter fat and happy.

But the die-off last fall that left numerous carcasses for coyotes to eat means there will be fewer deer around this winter for the hungry critters to scavenge.

And if the weather turns cold and snowy, that will put unusual pressure on the coyotes to find something — anything — to eat, biologists say.

“If we get a real winter, a severe winter, they’re going to be very hard-pressed. There’s going to be less food,” said Chris Anchor, a wildlife biologist for the Cook County Forest Preserve District.

So scientists will be paying very close attention to how the animals respond. They’re expected to adapt by eating everything from plants to rodents to garbage, but it isn’t unthinkable that their numbers will drop.

The forest preserve district has been involved for more than 12 years in the Cook County Urban Coyote Study — the nation’s most comprehensive look at the increasingly common canines.

During that span, Anchor and other biologists have captured and tagged more than 660 coyotes in Cook County in an effort to track where they live and what conflicts they cause with people and pets.

But the situation the animals face now is unusual because of a near-perfect storm of environmental factors, including last year’s mild winter and dry summer.

The weather may have created ideal conditions to spread the EHD virus, which is deadly to white-tailed deer, though it doesn’t usually strike in the Chicago area.

This year, the virus may have killed as many as 70 percent of the deer living in northern Cook County, Anchor said.

Coyotes aren’t affected by the virus, but have feasted in recent months on the carcasses of deer stricken by it.

The question heading into winter is how the coyotes will fare with one of their staple food sources dramatically reduced.

“Everything’s been scavenged now,” Anchor said. “They’re going to have far fewer roadkill around here. They’re going to be hit hard.”

That’s especially true if the Chicago area eventually gets heavy snow, Anchor said.

Nobody expects coyotes to disappear from the area slammed by the EHD virus simply because the canines eat so many different things.

“If one food supply dries up, they can move on to another. They’re probably one of the most resilient animals out there,” said Gina Farr, a spokeswoman for Project Coyote, a California-based advocacy group.

The critters aren’t picky about their meals — they’ll eat anything from rodents to unwary pets, deer carcasses or household garbage.

But coyotes can practically become vegetarians if necessary, subsisting on plant bark, roots, and even juniper berries.

“One of the reasons they are so successful is they are true omnivores,” Farr said, citing a study that found about 100 different types of food in the droppings and stomachs of coyotes.

Still, Anchor and other biologists will be watching to see if the number of coyotes drops in the area hardest hit by the EHD virus.

“Right now, they don’t need to do anything because they’re fat and happy. But come February, it’s going to be real interesting,” said Anchor.

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