Updated

A report that recommends killing feral cats as a way to control the animals, including a primer on how to shoot a cat, is stirring emotions among bird and cat lovers.

The University of Nebraska at Lincoln's study found that neutering or spaying is ineffective at eliminating feral cat colonies, though useful in reducing colonies' expansion.

One official from the American Bird Conservancy calls the report "a must read" for communities with a feral cat problem.

But critics note the wild cats help control rodent populations, and say habitat destruction, herbicides and other issues are a bigger threat to birds.

They also question the report's finding that feral cats' killing of birds costs the U.S. $17 billion, when accounting for how much bird watchers, hunters and others spend on the hobbies.