"The river levels were coming right up and the birds were sitting in nests that were in water.
"So immediately the regional council cleared the river mouth and the water level receded. So they saved the day – they actually saved the colony."
A feral cat was live captured after killing several birds but then a bigger threat arrived.
"The next major thing that happened was a major north-easterly storm on January 5. High seas, king tide – not a good combination – wiped out the whole nesting site.
"We counted four chicks out of 170 and we were a bit devastated by that."
But most chicks had been able to paddle to safety. They were found hiding in some long grass upstream, and with a little supervision from adult birds, soon made their way back to the river mouth.
"They form little creches and they have adults surrounding them and they corral the chicks back to a safer site."
The black-billed gull has been known to pick up scavenging habits from their red-billed cousins, but generally are quite different.
"They live on invertebrates – on bugs and a little bit of fish. They feed in a little more natural way.
"That is why their population is declining to a degree, because a lot of their natural habitat isn't there anymore."
Dogs and their two-legged companions are a constant threat, but the birds at the Haumoana colony are almost all fully mature and expected to soon leave to make their own way in the world.
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