According to recent news reports, Twin Cities' cat lovers are objecting to local rules requiring cats to be leashed or otherwise controlled when outside, citing what they say is tabby's natural desire to be free of household confinement.

But the outdoors may prove deadly to wildlife — and to the kitty.

Despite domestication, cats have retained their natural hunting instinct and are responsible for killing hundreds of millions of songbirds every year in the United States.

In Minnesota, an estimated 3.5 million pet cats may take more than 35 million birds and as many as 65 million small mammals. Feral cats kill even more.

But in the outdoors, cats (even dogs) are increasingly vulnerable to a predator that few may expect: coyotes.

"The public has no idea how many coyotes are around them," said Jim Lawrence, owner of Catch 'em 4 U Wildlife Control. Lawrence said coyote populations have increased significantly in urban areas over the last 20 years, and pets are easy prey for them.

"We hear more and more reports of pets being taken by coyotes," said Lori Naumann with the nongame wildlife office of the Minnesota Department of Natural Resources.

Coyotes generally prowl at night when few people see them, and that's when pets are especially vulnerable.

Lawrence said that coyotes are territorial and will seek to keep other canines, including dogs, away. In springtime, he said, denning coyotes are especially aggressive and will attack during the daytime, even when humans are around.

Naumann said that household cats that are kept inside have no natural desire to go out, but outside they are vulnerable to a variety of dangers including disease and cars.

Naumann added that well-fed domestic cats kill birds and other wildlife for pleasure.

A University of Wisconsin study gives a broader perspective: "Worldwide, cats may have been involved in the extinction of more bird species than any other cause, except habitat destruction." The University of Florida Conservation Clinic, in a report to the Fish and Wildlife Service, estimated that a free-roaming cat kills 100 mammals and birds per year.

Naumann said that more recently the DNR has become aware of a new and unexpected danger to birds — bullfrogs.

She said large bullfrogs from Texas are sold at some pet and landscape stores to be kept in backyard ponds. The frogs, that can weigh up to a pound, have voracious appetites and are known to take birds.