Trying to count cats is a bit like trying to herd them — nearly impossible.

But a group of unlikely collaborators, including wildlife supporters and animal advocates, worked together on a three-year project called the “D.C. Cat Count” to do just that. And their results are in: There are roughly 200,000 cats in the District.

Their project is one of the few in the country where a city has tried to get a thorough head count of felines. It was done to help the groups get a better handle on where — and how — cats live and how best to care for them, organizers said.

Counting cats is no easy task.

A variety of measures were used. Roughly 2,600 households in the city were surveyed as to whether they own cats.

More than four dozen animal rescue and wildlife staffers, along with volunteers followed cats in alleys and wherever they roamed to try to track them for a head count. And throughout the city, in ditches, trees, streams and alleys, organizers set up specialty cameras that are typically used to track wildlife to capture photos of cats as they passed by.

Equipped with digital memory cards, the cameras snapped roughly 1 million photos that organizers and volunteers then sorted. But the small cameras, which are triggered by movement, didn’t just pick up cats: They snapped photos of coyotes, deer, foxes, beavers, squirrels, raccoons, opossums, a mouse, a wild turkey and even a bobcat along the C&O Canal near the Palisades neighborhood in Northwest Washington.

The key, experts said, in counting cats was to make sure the same feline wasn’t being counted twice. Counters were trained to look for such features as fur patterns, body type, or other unique traits like a bent ear.

The D.C. Cat Count was organized by the Humane Rescue Alliance, PetSmart Charities, the Humane Society of the United States, American Society for the Prevention of Cruelty to Animals (ASPCA), and the Smithsonian Conservation Biology Institute. The project was paid for through donations from several animal advocacy groups.

The idea for doing a cat count came after ongoing, intense debates between conservationists and animal advocates. One side worries that cats kill birds and other wildlife. Their opponents argue that outdoor cats get a bad rap and lead a tough life trying to survive in the concrete jungle of a city.

It makes “a recipe for conflict,” said John Boone, a research coordinator with the Great Basin Bird Observatory who also worked on the D.C. Cat Count. “Sometimes each side of the cat debate sees the others’ view as a threat.”

In D.C., the debate about cats living indoors versus outdoors and how best to manage them goes back nearly 100 years, according to Lisa LaFontaine, the president and chief executive of the Humane Rescue Alliance. In 1929, the city enacted a law that “all outdoor cats found running at large shall be seized and destroyed,” LaFontaine said. “That was the framework of cat management for many years.”

“Good Samaritans started feeding the cats and entire colonies of cats,” LaFontaine said. But cats can have multiple litters in a year, and a population that’s “uncontrolled and without intervention can get really, really big, really fast and out of control.”

In the mid-2000s, the city started to a “trap-neuter-return” program to try to get a burgeoning outdoor cat population more in control, LaFontaine said.

One of the biggest debates in how to deal with feral cats was trying to figure out just how many there are and how to better house and care for them.

The cat count project had several interesting findings, organizers said. One of the overarching themes in the analysis was that much like for humans, there are socioeconomic factors that are “good predictors of where outdoor cats live,” said Tyler Flockhart, an ecologist and conservation biologist who helped with the D.C. Cat Count.

Here are some of the project’s findings:

· Of the roughly 200,000 cats counted in the District, about 197,000 of them are cared for by humans, and the rest are considered feral or strays.

· For those cats in human care, about 104,400 of them stay inside always. Another 72,900 cats go outside sometimes, and another 19,700 cats are considered “always outdoors.” The “always outdoors” cats may have owners, or some are fed by people in the community.

· Outdoor cats are less likely to be found in wealthier neighborhoods, and they’re unlikely to be found in large parks.

· Cat ownership was highest for D.C. residents who are in their 40s.

· Areas in the city with less dense housing and high median incomes tended to have a higher number of cats per household.

· For cats that are taken into shelters, most of the ones brought in come from the east and south sections of the District, and they usually get adopted by residents living in the city’s central and northwest areas.

The techniques and methodology behind the D.C. Cat Count were shared online in what organizers call a “tool kit” that’s available free of charge to other animal rescue and wildlife groups. They said they hope it provides helpful guidance and resources in how to get a handle on an area’s cat population.

The tool kit includes suggestions on how to do camera studies of cats, run household surveys, form partnerships with groups that can help in data collection and analysis, how to count cats and take photos of the felines, too.

Chris Schindler, vice president for field services at the Humane Rescue Alliance, said the cat count and its research “really help us to better understand where cats live and where we can place our resources.”