Thousands of rare black billed gulls are nesting near the Ashburton River mouth and also at the State Highway One bridge.
It is not just black billed gulls that call the Ashburton River home at this of the year, but also other less obvious native birds like endangered terns and dotterels.
The most easily seen are the black fronted tern, said Edith Smith from Ashburton Forest & Bird.
The birds are found only in New Zealand and rely on the braided rivers for nesting.
They lived on shingle islands and in small colonies, with nests spaced away from one another, Mrs Smith said.
"They hawk insects over the streams and feed on small fish.
"They become agitated when disturbed and dive bomb intruders and they are known to abandon their nests and eggs when unsettled.''
The banded dotterel was another endemic species that bred only in New Zealand on our braided rivers.
They were known for their broken wing display when their nest were threaten, said Mrs Smith.
A self introduced native black fronted dotterel had made itself at home in the Ashburton river too and had a bright orange bill with a black tip and had a black mask across its eyes making it an attractive bird.
Braided river birds' nests are made of twigs in a small basin in the shingle and are not in obvious colonies and are difficult to see when driving.
It is an offence under the Wildlife Act to disturb the native birds.
Signs are up in various locations along the Ashburton River to remind people of bird activity and to keep dogs on a lead.
