Dead ducks and seagulls in Whangārei suburb victims of natural causes

More than 60 birds have died from avian botulism in Tikipunga, with several dead ducks left to rot in the Totara Parklands stormwater pond. Photo / Michael Cunningham

More than 60 birds that died in a Whangārei suburb are likely victims of avian botulism, with the outbreak caused by hot, dry weather.

For the last month, ducks, seagulls and a signet have been struck down by disease at Totara Parklands and the wider Tikipunga area.

Totara Parklands resident Gareth Blithe became alarmed when he saw dead ducks in the suburb’s stormwater pond off Wairau Dr on Saturday.

“We were walking with the family on Saturday morning, and we counted eight [dead ducks]. I thought it wasn’t the norm.”

Blithe was initially concerned the birds were poisoned and put a post up on social media, but he was soon educated about avian botulism.

“It’s the first time we’ve seen anything like this and we’ve been here six years. Originally, it was quite concerning when you see a whole lot of dead birds in a small area.”

A botulism outbreak is triggered by environmental conditions - including hot weather - which prompts a naturally occurring bacteria to produce a toxin deadly to birds, according to the Department of Conservation (DoC).

Outbreaks stay localised and clear naturally with rain and cooler temperatures.

Ministry for Primary Industries biosecurity surveillance and incursion manager Wendy McDonald said Biosecurity New Zealand was notified three times in March about dead birds in Tikipunga.

Its main role is to determine if any exotic bird disease is involved in the deaths, and tests to date have shown no sign of this, she said.

“Large numbers of dying birds are not uncommon and can have environmental causes such as algal blooms and botulism.”

Whangārei District Council said there is no sign of a deadly blue-green algal bloom.

Dead ducks left at Totara Parklands could spread an outbreak of avian botulism to other birds, Robert Webb warns. Photo / Michael Cunningham

Red-billed gulls that were still alive were taken to the Whangārei Native Bird Recovery Centre, where about 10 were saved but about 50 died, said manager Robert Webb.

About 10 New Zealand scaup ducks, or pāpango, also died along with a black signet and Webb said there could also be others that he doesn’t know about.

He confirmed the birds are victims of avian botulism caused by the hot weather, which has dried out the Totara Parklands pond.

“Botulism is very common this time of year – it’s the heat that does it and warms up the water. If the rivers aren’t flowing, the birds eat it [the bacteria].”

The seagulls that were saved were found at an early stage of the disease. About 10 have been released back into the wild but one remains at the recovery centre – possibly a “freeloader” which has learnt about the centre’s easy meals, Webb said.

While the botulism outbreak is natural, he said someone should safely dispose of the dead birds to stop it spreading, a practice also encouraged by DoC.

However, gathering up dead animals has health and safety risks and it is best to let nature take its course, said Whangārei District Council wastewater and stormwater operations manager Andy Keith.

“A good wet spell will help to sort the situation out. We will, however, continue to monitor the situation in case anything in our approach needs to change.”

The stormwater ponds are designed to protect properties from flooding, and are large and shallow so they can dry out between rain events, with the stagnant water sometimes smelling, Keith said.

People and pets should keep away from dead birds, and people should report any large numbers of sick or dying wild birds to Biosecurity NZ on 0800 80 99 66.

Denise Piper is a news reporter for the Northern Advocate, focusing on health and business. She has more than 20 years in journalism and is passionate about covering stories that make a difference.