Alejandro Prieto has spent nearly 16 months camped out near the wall along the U.S.-Mexico border, where he has documented the barricade’s effect on bobcats, jaguars, sheep and other animals.

He was driving on the U.S. side of the border wall near Naco, Ariz., about two years ago when a roadrunner darted out of the vegetation. Prieto, a wildlife photographer from Guadalajara, Mexico, grabbed his camera as the speedy bird stopped in the middle of a gravel road.

The roadrunner appeared to gaze at the tall barbed-wire-covered wall that cut through the desert. It was there just long enough for Prieto to snap a few shots.

“It was a fleeting moment but full of emotions,” Prieto told The Washington Post.

One of those photos — which he named “Blocked” — received the top prize this month in the annual Bird Photographer of the Year awards, a global competition celebrating avian beauty. It was selected from more than 22,000 submissions.

The Trump administration built 455 miles of new barriers along the Mexico border, which conservationists warned could affect wildlife and vegetation. Department of Homeland Security officials in 2017 sought an environmental waiver to build a 15-mile stretch of the wall near San Diego. The Center for Biological Diversity, an environmental advocacy organization, called the move a “dangerous disregard for our environment.”

In a February 2020 hearing on Capitol Hill, Rep. Kathleen Rice (D-N.Y.) said the Trump administration used DHS’s waiver authority “16 times to ignore laws designed to protect the environmental and cultural integrity of communities.”

The Biden administration announced in January that new construction on former president Donald Trump’s signature infrastructure project would be paused. Three months later, a judge ruled that the federal government could seize a Texas rancher’s land near the border, renewing landowners’ concerns about the project.

Prieto, who has been documenting wildlife for more than 20 years, has been on a mission to show how plants and animals along the U.S.-Mexico border have responded to the barriers. A lot of attention was placed on how the wall would affect immigration and drug smuggling, he said, but he worried about the natural ecosystem.

“I felt I needed to give a voice to all [these] creatures,” the photographer told The Post.

Documenting that has been difficult and dangerous, he said. He has not only braved bad weather, bobcats and jaguars, but also drug smugglers, camera thieves and border patrol agents. But he is committed to the work, he said.

“My job is to get these kind of images, powerful and different images, hoping to provoke actions and changes,” Prieto said.

“Blocked,” according to Bird Photographer of the Year, tells an important story about how man-made structures can prevent wildlife from moving about.

“The wall dominates the image, with the roadrunner seemingly powerless and small in the frame,” the award announcement states.

Prieto sees in the photo the “fragility and innocence of wildlife against the dark side of the human being.”

“Blocked is exactly what is happening to different animal species that live in this area,” he said. “Animals need to move freely from one place to another in order to find food, water [or] … better weather conditions.”

He recalled seeing a bobcat at the San Bernardino National Wildlife Refuge in Arizona interacting with another section of the border wall. At the time, he said, there were gaps in the barrier where wildlife could move between the United States and Mexico. It has since been “replaced by a big wall,” he said.

“We saw a bobcat crossing from one country to the other on a daily basis,” Prieto said. “After weeks, we found out it was a female with kittens. She was going to [the United States ] in search of food and going back to Mexico to feed her young.”

Aside from the roadrunner, Prieto has also snapped images of rabbits, raccoons and wildcats against the backdrop of the border wall. He said he hopes posting them on Instagram and his website allows people around the world to better understand what’s happening on the border.

“My goal in life,” Prieto said, “is to spread a conservation message.”