And their movements around Hawke's Bay have been noticed for some of their unusual choices.
The birds were in the news recently after five were found dead at Rotorua's Sulphur Bay during a routine check by a Department of Conservation volunteer in mid-November last year. Officials believed the gulls were shot.
They were more commonly found in the South Island, breeding inland on shingle riverbeds. But last year, a colony was found breeding in Hawke's Bay.
Their Hawke's bay breeding site was out of character - the Tukituki Rivermouth, exposing them to humans, predators and surf.
The black-billed/tarāpuka seagull was classified as nationally critical in 2013, with the next move downhill being extinction. Photo / Patrick O'Sullivan
Against the odds the colony grew. Soon after fledging early last year, some of the birds began visiting the building across the road from Singh's dairy on Heretaunga St East, where they observed him feeding sparrows.
"I like to do something for the birds," he said. "Before I was just feeding the little birds, but now seagulls are coming in."
The gulls didn't return to the Tukituki Rivermouth to breed, choosing instead a more traditional nesting site, well inland on the Ngaruroro Riverbed, where they were flooded out twice in November.
The devastated flock spied another site at the Westshore Wildlife Reserve, recently created thanks to the new entrance to Hawke's Bay Airport, so the birds relocated yet again, to this man-made site.
"We had all this gravel as part of the building of the road on the other side," Napier City Council Parks Assets Planner Jason Tickner said. "It seems we are getting species here that we haven't seen here before, so we are very happy."
Success for the Westshore colony was about to be declared but the birds mysteriously abandoned their gravel spit for a shore-side berth, leaving them more vulnerable to predators.
