Park manager Paul Kavanagh said the bird, one of the rarest gulls in the world, was dropped into VetEnt in Frankton, where it was assessed by vet Orla Fitzpatrick.
Mr Kavanagh said the bird was quite ``banged up''.
``There was definitely an impact injury. There was a bit of a laceration and a bit of swelling on the wing but it was also quite malnourished and we think it was maybe [injured] in the recent storm. That tallies up with dates.''
The bird was treated at the Queenstown park for two weeks. It was given anti-inflammatory medication and fed via a tube.
Mr Kavanagh said the local gull population was healthy but numbers had declined by as much as 80% elsewhere.
``Not many people know this, but even though we have a decent population around Queenstown they are actually the rarest gull in the world.
``We get them locally so people don't realise just how rare they are. Everyone thinks it is just another seagull, but they are bloody rare.''
The main threats to the birds are rubbish, introduced predators and members of the public disturbing nests on braided rivers.
``People need to be really careful about disturbing nests around the Shotover River and Tucker Beach and be careful with dogs.''
The gull was released beside Lake Esplanade last Thursday.
