Bell, a female peregrine falcon, was taken to Wellington Fire Station by owner Karl Jennings after outgrowing the metal band placed on her leg at birth.
Firefighters had to use specialist cutting equipment to remove the ring because her owners could not get hold of their usual cutters.
Mr Jennings, a vet at Vets Now, in Haygate Road, Wellington, said: "We have got her as part of the captive breeding project.
"What we do is when the birds hatch you cannot tell the difference between male and female so we put two sizes of rings on them. It is normally not a problem but she is looking like she is going to be a pretty large female bird.
"Males are generally smaller than female birds so there is quite a significant size difference but we cannot tell that straight away.
"This is a hobby but peregrine falcons are a particular passion of ours and we have rescue birds as well.
"We have got friends who normally have got the tools but we could not get hold of them and we needed to do this pretty urgently.
"We went to the fire station and I just asked them if they could do it if it was not to much trouble and they did it quite easily."
Mr Jennings said the bird would now be left to grow up until it was old enough to breed. He added: "We have got 15 of them at home. They are the fastest creatures on Earth. It can stoop up to 200 miles an hour so they are quite majestic creatures.
"I have been rehoming and rescuing birds since I was eight-years-old, I used to have a falconry centre and I am now a vet."
Watch manager Scott Bishop, of Wellington Fire Station, said: "No job is too small.
"We had a phone call from the owner to say that they had a bird with a metal ring around its leg.
"Due to the growth rate of the bird it had to have this removed quite urgently. So we used our ring cutter to remove it. We have to get the ring cutters out a lot but mostly for people getting rings stuck on their fingers, not for birds, that is quite rare."