What would St. Francis do?

Is it time to leash your cat? A new study documents the terrible damage that cats do to the bird population. As reported in The New York Times:

While public attention has focused on wind turbines as a menace to birds, a new study shows that a far greater threat may be posed by a more familiar antagonist: the pet house cat.

A new study in The Journal of Ornithology on the mortality of baby gray catbirds in the Washington suburbs found that cats were the No. 1 killer in the area, by a large margin.

Nearly 80 percent of the birds were killed by predators, and cats were responsible for 47 percent of those deaths, according to the researchers, from the Smithsonian Institution and Towson University in Maryland. Death rates were particularly high in neighborhoods with large cat populations.

Predation was so serious in some areas that the catbirds could not replace their numbers for the next generation, according to the researchers, who affixed tiny radio transmitters to the birds to follow them. It is the first scientific study to calculate what fraction of bird deaths during the vulnerable fledgling stage can be attributed to cats.

The rest of the article is here. So what it is to be done? Some people in the Capital District have proposed that cats must be on a leash whenever they are outside. Is this an idea who time has come?