A flow of excrement is among reasons red-billed gulls are failing to find favour with businesses and residents in Oamaru.
People have been screwing their noses up at flocks of seagulls nesting in the centre of the seaside town.
Building owners have been called on to put preventative measures in place, but hundreds of birds still dominate gutters and alcoves.
The red-billed gulls are a protected native species under the Wildlife Act, meaning their nests cannot be moved once eggs have been laid.
Waitaki region mayor Gary Kircher said the gulls were causing more chaos than the town would like. The birds tended to be territorial, swooping on people if they came too close to their nests.
"The noise is very disruptive and the excrement they spread around is not appreciated either so a few issues."
He agreed they were smelly, noisy and disruptive.
There was a significant amount of wildlife in Oamaru, especially around the harbour, including little blue penguins, rare Otago shags, seals and fairy terns, Kircher told Morning Report.
"There's some great things about that but when they start moving into our space, particularly the more aggressive red-billed gulls, it's a problem."
It meant building owners and tenants in the CBD needed to get onto their roofs and prevent nests being built.
Deterrents they could use included bird-shaped kites, spikes along parapets and movement activated sprinklers on roofs.
"So a range of different things but it does require a bit of dedicated effort and if everyone did it we'd be fine - they'd go and find somewhere else to nest and to scavenge. But the problem is a lot of people are doing a really good job of it and some just aren't."
An area for the seagulls had been created on a hill above the town and this had proved quite successful but the gulls liked to go where the food was and where they could avoid predators so up on shop roofs seemed to fit the bill.
In 2020 a former deputy mayor of Oamaru called for a law change to allow the gulls to be culled, saying he was fed up with the sight of bird excrement on buildings, roads and footpaths in the CBD.