In the height of the summer heat in February, two NSW National Parks and Wildlife Service officers were spraying weeds in Warrumbungle National Park near Coonabarabran when something in a creek caught their eye.

It was a bird with its wings slightly open, barely moving a muscle. It was a huge bird - our biggest, a wedge-tail eagle.

The eagle didn't move, didn't attempt to fly away when they approached.

Knowing something was wrong they took the bird and drove several hours to the Taronga Western Plains Zoo in Dubbo.

Zoo staff noted yhe bird - a young male - was unwell, and had very cold feet but X-rays showed he didn't have any apparent injuries.

The bird was weak and a little underfed. The staff started giving it food, water and antibiotics.

"It may have been poisoned, and it might have been sick; it could have had a knock to the head, we are not sure," a Taronga Western Plains Zoo spokesperson told the Western Plains App.

"Wedge-tail eagles are scavengers, so if they pick up a fox, a dog or a pig that has been poisoned, there is a chance they can get poisoned also," she said.

Wedge-tails are widespread across the western plains. IMAGE: Australian Museum

Hospital staff gave the creature blood tests and more health assessments. They were still unable to find what was wrong.

But after ten days of regular feeding and care the bird took a turn - it started to sit up in its cage, looking brighter and better.

After two weeks, he was released back into the wild. Not far from the creek - which he didn't return to. He flew up right into the sky.

Wedge-tailed eagles are found in many parts of the Western Plains, most commonly in open woodland areas with thick grassy ground cover.

"If he hadn't been found by brought into the wildlife hospital, he probably would have died," the spokesperson said.