For two hundred years, the blue-and-yellow macaw has been everywhere in Rio de Janeiro except the one place it belongs.

That changed this year, when four of the birds lifted out of an aviary inside Tijuca National Park and climbed into the canopy of the Atlantic Forest.

Tijuca is Rio’s largest urban park. It’s a 10,000-acre pocket of tropical forest pressed up against one of the world’s great metropolises. It’s an immense sanctuary, where once you’re inside, you’ll forget you’re in the middle of one of the world’s biggest cities, where the traffic noise completely fades away. Ecologists from the Brazilian conservation group Refauna have spent years rebuilding the animal life that was poached or driven out of these mountains during the 19th century. Howler monkeys are back. So are red-rumped agoutis and yellow-footed tortoises. Each reintroduction has pulled new visitors onto the trails.

None of them has stirred the city like the macaw.

“They are so magnificent. It’s no surprise that all the visitors are constantly asking how they can see them,” Viviane Lasmar, the director of Tijuca National Park, told the Guardian. “For me, as the head of the park, it’s special. But even more so as a carioca. It’s a dream come true.”

The four birds Refauna released had been rescued from captivity, and captivity had taken a toll on their flight muscles. A wild macaw can cover six miles in a day foraging for food, and these ones were not ready for that kind of work. After fifteen days out in the forest, the team coaxed them back into the aviary to keep building strength and to learn the calls, scents, and fruits of a home they barely knew. If all goes well, a permanent release is planned for September, when food is most abundant.

The ecological stakes reach beyond four birds. The Atlantic Forest, once as rich in species as the Amazon, has been cut back by roughly 90 percent since the colonial period. A macaw’s heavy beak cracks open nuts and fruits and scatters the seeds along its flight paths, a service nearly every tree in Tijuca relies on to reproduce. Return the seed-carriers, and the forest can begin to rebuild itself.

“The macaw really is a symbol of our efforts to bring life back to Tijuca,” Marcelo Rheingantz, the executive director of Refauna, told the Guardian. “My dream is that one day they will fly far away from here and we will be able to see them from all over the city.”