Whangarei's Native Bird Recovery Centre says backyard bird poisoners are distressing their neighbours by killing off the birds that flock to suburban gardens.
Robert Webb said many elderly people fed the birds and liked to see them turn up every morning for breakfast.
But he said there had been a spate of mass poisonings lately by others who do not like the birds, and buy readily available poisoned wheat to kill them.
Mr Webb said sparrows, blackbirds and thrushes had been brought into the centre by people who have found the birds thrashing around in convulsions on the road, or their lawns.
He said he had no argument with the owners of supermarkets and warehouses who need to cull birds when they become a health hazard, but felt it was mean-spirited to kill the garden birds, and that lone suburban bird-killers should not be able to buy the poisoned wheat.