Dr Chris Lalas monitors red-billed gulls nesting in Otago and found only seven to nine nests in the CBD during the 2023 breeding season.
That is down from the 150 nests estimated in 2022.
It bird-proofed many of the buildings and continues to conduct regular checks on roof spaces.
New bird netting has also been added to the Forrester Gallery following its cleaning.
These changes appear to be working as not only are nest numbers lower in the CBD, they are also rising elsewhere.
It appears the seagulls have set up a colony at Graves Track as estimated nest numbers have grown from 587 nests in 2022 to about 1334 nests in 2023.
These estimates are made using visual inspection and aerial photos of the site.
As the 2024 breeding season approaches, the council is encouraging building owners to remain vigilant about new nests forming.
Routinely checking their roofs and making sure their bins were secure were easy ways to make sure the seagulls did not return to the CBD, a council spokesman said.
"Human food isn't good for wild birds, and gulls will always hang around in areas where food is easily available."
If nests are formed, people are allowed to remove them but only if they do not contain chicks or eggs.
Red-billed seagulls are a native, protected species that are nationally in decline.
The spokesman said the council’s intention was not to get rid of them, but to encourage them to find a more suitable natural habitat.
