Poisoned seed was used to kill birds
The birds – native and non-native species – were found over several days last month by Lismore woman Jan Harrison while walking her dog.
Ms Harrison then contacted Lismore City Council, which in turn contacted the DPI to conduct an autopsy.
The DPI results showed that the bird it examined had ingested seed containing the organophosphorus insecticide 'fenthion'.
According to an Australian Government website, fenthion is used to kill pest insects in horticultural production, home gardens and around commercial buildings, as well as controlling non-native birds nesting or roosting in commercial and industrial buildings. It is also used in a spot-on formulation to control fleas on dogs and external parasites on cattle.
Lismore Council's Co-ordinator of Environmental Health and Regulation, Matt Kelly, said it was a non-selective poison and would kill any bird that came in contact with it.
Mr Kelly has now referred the matter to the NSW Department of Environment and Climate Change and is waiting to hear back as to whether the department will send someone to investigate, or will advise what further steps can be taken.
Council parks and garden staff had not seen any loose seed in the area where the carcasses were found and the birds may have been poisoned elsewhere, Mr Kelly said.
Jan Harrison told The Northern Star she saw another dead bird under the bridge on Monday; the first she had seen in nearly two weeks.