Don’t worry, wildlife would kick undead ass:

…zombies are essentially walking carrion, and Mother Nature doesn’t let anything go to waste.

Yup.

[Update a few minutes later]

It’s really worth a read:

North America’s large mammal predators would be more than a match for zombies. We have two bear species, brown (or grizzly) and black bears. Male brown bears can weigh in at 1,000 pounds. They are not afraid of humans. They can deliver a bite of 1200 pounds per square inch and have long, sharp claws designed to rip open logs and flip boulders in search of insects and other small critters to eat. They would easily tear apart rotting zombie flesh. Black bears are much smaller and typically run from humans, but even a black bear, when approached or cornered, would make short work of a zombie. Both bear species have an incredible sense of smell and both love to eat carrion, so even if zombies didn’t approach them, the bears eventually would learn that these walking bags of flesh make good eating.

Like black bears, gray wolves are very shy of humans and typically run away at the first sight of us. Nor are they strangers to scavenging. They’d soon take advantage of the easy pickings presented by lumbering zombies. Coyotes are far less shy than wolves and can happily live alongside humans, including in the heart of our cities. These intelligent canids would quickly learn that they could take down zombies one by one, especially the eastern populations of coyote, which are larger and bolder due to past interbreeding with wolves and domestic dogs.

Though I’d point out that it they think black bears are shy around humans, they’ve never run across one in Alaska. They’re very aggressive up there — Alaskans seem to fear them more than grizzlies, which will generally leave you alone if you don’t surprise them. I suspect it’s because they’re much less used to humans, with the low population density. It’s almost like they’re a different species from the lower forty nine. Alaska would be a particularly gruesome place to be walking dead. The moose alone would make quick work of them.