The cafe replaced six coffees and four meals. "Not only that but there's also the damage to our glasses, wine glasses, bottles and plates."
Mr Edmond said the birds appeared to be getting braver compared to a year ago.
"They would still wait for people to leave before they ate any scraps. Now, I've seen one take bread from someone's hands."
Mr Edmond said sometimes the birds waited on the eaves of the cafe's roof and "fire-bombed" some customers sitting outside.
At Deckchair, manager Rochelle Clark said staff often warned people to be wary of the birds.
"They sit on top of the cars out the front and they just watch. And while people are eating, they just hover. They will just wait for their chance."
Ms Clark said birds had taken food from tables before because someone's hand was not on their plate.
"We shoo them away and try to clear tables as fast as we can. There's not much else we can do."
Sidetrack cafe owner Petra-Lee Osbourne said the birds were a big problem and a customer had given staff water pistols to use against them.
However, the birds appeared to know when staff had pistols at hand, she said. "I wouldn't say they are intelligent but if we are there with the pistols they don't come. As soon as we leave, they fly in."
Ms Osbourne said they encouraged customers not to feed the birds.
The red-billed gull is listed as a nationally vulnerable New Zealand bird on the list of threatened birds.
A Tauranga City Council spokeswoman said their health inspection team encouraged cafes to remove leftover food, used plates and cutlery from outside tables as soon as possible.
Similarly, they encourage cafes to discourage patrons from actively feeding the seagulls, she said.
Bay of Plenty medical officer of health Neil de Wet said birds could carry bacteria such as salmonella and possibly campylobacter, which can cause vomiting and diarrhoea.
Dr de Wet advised people to do what they could to discourage the seagulls and not to eat food touched by the birds.
Seagull facts:
The red-billed gull or tarapunga (Larus novaehollandiae) has a white body with grey wings tipped with black then white. Their bills and legs are red. They are 37cm long - considerably smaller than black-backed gulls. Males weigh 300 grams and females about 260 grams. They are considered tapu by Te Arawa iwi and can live up to 25 years (source).
What you can do:
• Don't feed birds, even sparrows, as this encourages them to eat people's food.
• Don't eat food touched by a seagull as they can carry harmful bacteria diseases such as salmonella.
• Ensure your eating surface has been cleaned adequately of bird droppings.