Rio the red kite was found near Leitrim, County Down, with an infection in her foot.
It meant the bird could not flex her talons, which affected her ability to feed.
She became weak and unable to fly.
She was reintroduced to the wild after being treated by a vet.
Rio was one of 80 red kites introduced to Northern Ireland and has raised five chicks.
She is important to the programme because she has bred consistently since her release.
The red kite has been under pressure in south Down since its reintroduction in the years between 2008 and 2010.
Three birds have been shot, a further 12 have been poisoned and 12 more have been found dead with no clear cause.
There are just 12 breeding pairs, well short of the 50 pairs experts say are required for a sustainable population.
Claire Barnett is a senior conservation officer with the Royal Society for the Protection of Birds (RSPB).
She said they have tried hard to get the message across that the birds do not pose a threat to livestock - especially lambs.
"The bird actually has small, weak feet so there's no way they're going to be able to pick up anything bigger than a small rabbit.
"Their main diet is made up is things like mice and worms and rats and road kill," Ms Barnett said.
There is some good news though - the breeding pairs have produced 71 chicks and RSPB staff said there is evidence that the birds have begun to spread out.
They are asking the public to send them details of any sightings.
Red kites are quite distinctive. They have a five and a half foot wingspan and a deeply forked tail.
A key member of a breeding programme, designed to reintroduce an impressive bird of prey in Northern Ireland, has been returned to the wild after being found injured in a field.