Just 15 miles from Spain's bustling capital city of Madrid, nestled in a lush public forest, is the GREFA animal hospital, the first stop for the country's injured, ill, or orphaned wildlife. Known as the Group of Rehabilitation of the Native Fauna and its Habitat, this non-governmental nonprofit is dedicated to studying and conserving Spain's native animal species.

A veterinarian weighs an orphaned duckling at its arrival to GREFA hospital on March 16, 2017, in Majadahonda, near Madrid, Spain. | (Pablo Blazquez Dominguez/Getty Images)

A coordinator feeds a 2-week-old orphaned fox cub. | (Pablo Blazquez Dominguez/Getty Images)

Spring is a busy season for GREFA. Indeed, warmer temperatures bring thousands of orphaned chicks and baby animals to the hospital. But all year round, the center takes in victims of human-caused injuries, mostly birds of prey, that may have been run over, poisoned, or shot. Often the hospital finds itself caring for rare and endangered species, like black vultures and golden eagles.

GREFA works toward recovery and re-release, but when that isn't possible, patients can be sent to zoos, reserves, or other facilities for educational purposes.

Since its founding in 1981, GREFA has treated more than 40,000 animals — more than 5,000 in 2016 alone — making it one of the oldest and most important wildlife hospitals in Spain, if not all of Europe. Below, peek inside GREFA's facilities and see how it's keeping the region's wildlife wild.

Veterinarians treat a Spanish Imperial Eagle with a broken wing. | (Pablo Blazquez Dominguez/Getty Images)

An orphaned rabbit gets its initial checkup. | (Pablo Blazquez Dominguez/Getty Images)

A Peregrine falcon with a broken wing. | (Pablo Blazquez Dominguez/Getty Images)

Veterinarian Laura Suarez treats a pond turtle that lost its eye. | (Pablo Blazquez Dominguez/Getty Images)

A Picogordo bird has its wing cleaned of glue with sand and a toothbrush after it got stuck in an illegal trap. | (Pablo Blazquez Dominguez/Getty Images)

Veterinarians and volunteers use a thermometer to take the temperature of a seagull. | (Pablo Blazquez Dominguez/Getty Images)

Veterinarians Laura Suarez (left) and Virginia Moraleda (right) treat a turtle in the reptiles room. | (Pablo Blazquez Dominguez/Getty Images)

A stork walks in its room during recovery. | (Pablo Blazquez Dominguez/Getty Images)

Veterinarian Virginia Moraleda leaves a Spanish Imperial Eagle in its room after it was treated for a broken wing. | (Pablo Blazquez Dominguez/Getty Images)