On a sunny spring day at the National Arboretum, Daniel Herrera is crawling on all fours.

As part of a team figuring out how many feral cats call the District home, Herrera, 24, seems to embody the elusive animal he seeks. Beneath a tree a few yards from the arboretum’s gift shop, he takes a few cautious steps — if “step” is the right word — while propped up on his hands, then bends down farther, his elbows touching the ground.

Herrera, a DC Cat Count field technician, is determining how far from the ground to place a camera on a tree branch — a camera that, when triggered by motion, will snap a photo of a feline or any other animal that crosses its path. He spent the day placing cameras in streams, ditches and anywhere there were signs of wildlife.

It’s a task he prefers to placing the cameras in D.C. alleys.

“We generally get just ankles,” he said.

Nine months ago, Herrera helped launch the DC Cat Count, a $1.5 million, three-year effort to document the lives of feral cats that roam Washington.

The count — organized by the Humane Rescue Alliance, the Humane Society of the United States, PetSmart Charities and the Smithsonian Conservation Biology Institute — seeks to figure out where cats live in the city so advocates can better help, house and manage their population. The project is funded through donations from animal-advocacy groups.

Even with the first year in the books — an exercise that yielded more than 3,500 images of cats — there is no official count, yet. After leaving the streets for the winter, cat counters ventured out again this week to embark upon their second year in the field.

In addition to thousands of felines, the DC Cat Count captured images of coyotes, foxes, squirrels, raccoons, opossums and deer frolicking on the District’s stoops and in its sylvan glades.

Lauren Lipsey, vice president of community programs at the Humane Rescue Alliance, called the cat count a “monumental project” that seeks “to understand the flow of cats, outside and inside, and into the shelter system.”

“We really can’t pretend to have data-driven policy for how we are going to support and manage the outdoor cat population,” she said. “There are a lot of questions that a baseline cat population will help us attempt to answer.”

To find the cats, researchers deploy 60 cameras, each about the size of a small lunchbox, in three-block sectors of the city. The cameras are attached to trees or fences, chained with cable locks and left to record animal revelry on digital memory cards.

Starting this year in Northwest Washington, the cameras will move every two to four weeks until they reach the entire District. Supplemented by a survey of residents, organizers say they should be able to produce a final cat count in 2021.

Herrera said officials need to capture 70 percent of the feral cat population each year to keep it under control. Many cats are neutered and released, while social cats are put up for adoption.

Left unchecked, cats, which are considered predatory, can lay waste to the bird population.

Grant Sizemore, director of invasive species at the nonprofit American Bird Conservancy, said cats are “among the world’s most harmful invasive species.” Outdoor cats kill 2.4 billion birds each year in the United States, have contributed to the extinction of 63 species and are a leading source of rabies in the United States, he said.

“The only way to really protect wildlife is to keep cats safely indoors,” Sizemore said.

Though the arboretum doesn’t appear to be a hotbed of feline activity — and Herrera said he doubts the two field technicians will catch any in action — surveying these idyllic acres is as important as posting cameras in cat hangouts.

“It’s equally important to know where cats are not,” he said.

William J. McShea, a research ecologist for the Smithsonian Conservation Biology Institute, said the program is proceeding as planned, with scientists overcoming procedural hurdles like getting permission to place cameras in alleys.

“We’re generating a lot of pictures,” he said. “Some neighborhoods are full of cats. The next part is: Can we tell the cats apart?”

To tell the difference, McShea said researchers borrow techniques from tiger biologists, tracking coat patterns to figure out whether they’re seeing similar-looking animals or the same animal twice. If this technique fails, as it does in the case of black cats, for example, scientists use shelter data to figure out what percentage of the population the uniformly colored cats represent.

“We’re not counting all the cats — we’re estimating their distribution,” he said.

Cat and wildlife enthusiasts can follow the process on Instagram at @dccatcount, and those interested in hosting cameras can sign up at the DC Cat Count website. The group’s second field season will wrap up when the weather turns cold, with the final year beginning next spring.

Read more: