What’s ailing the little owls of Auckland?
As NZ Bird Rescue cares for record numbers of ruru/morepork at Auckland, one theory is they're being poisoned
Amin Izadkhah says finding a bright-eyed ruru outside a friend’s house in Hillcrest on July 12, was an adventure.
Izadkhah received an urgent call to come help, and was then enthralled to discover the bedraggled little nocturnal hunter hiding behind a bin on his friend's porch.
The architect who works as a building surveyor at Auckland Council, says he was needed to help nab the morepork (since dubbed “Rosie”), before one of the grumpy neighborhood cats got to her.
"Rosie fixed me with a belligerent stare from her enormous eyes and seemed to be trying to scare me off, but she didn't peck when I carefully scooped her up," says Izadkhah.
“I felt favoured meeting one of these secretive animals. I just forgot about work for an hour or two and began calling around, trying to find a vet who would treat her.”
Eventually this meant a journey to St Lukes, the vet then passing the ruru on to NZ Bird Rescue in Green Bay.
Rosie has since made a full recovery and been released back into the wild, but for a day or two she was among 12 morepork convalescing from various (known or suspected) causes at the facility’s bird hospital.
And though the origin of this owl influx can’t be proven, the charity’s manager Dr Lynn Miller, has her suspicions.
The scientist and toxicologist, who has much experience working with owls overseas, says ruru mainly feed on insects but are also known to enjoy feeding on carrion.
“For example, dead mice or rats, and I think that's the trouble,” says Miller.
“A morepork can easily dismember a mouse, using its powerful talons and sharp beak. And please do remember that if ever you want to help one, I’d say pick it up gently, perhaps using a towel to protect the bird and your hands.”
Miller’s career has included working alongside Gerald Durrell at the Jersy Wildlife Preservation Trust and also at London Zoo. She helped rehabilitate wildlife following the disastrous 2010 Deepwater Horizon oil spill in the Gulf of Mexico and has worked extensively with owls and other wildlife in Canada.
She suspects many of our native morepork get sick following a feed of rat or mouse meat, the animals having been poisoned by caring Aucklanders.
“Yes, they also get wounded by cats, or bash into windows during flight, or get struck by cars. That last one happens a lot to morepork during nocturnal expeditions to chase swarms of insects attracted to Auckland street lights."
But reports of poisoned birds are ramping up, she adds.
“It’s wonderful more Aucklanders seem to be taking the initiative to control the pests around their properties. Rats and mice are a major threat to all native wildlife, including morepork.
"But we’re finding residues from rodent poison - such as brodifacoum - in the bodies of animals that feed off carrion (hawks and ruru). This blood thinner can kill the bird or make it unwell, with the residue lasting maybe up to a year in the bird’s liver.
“It’s not that people should refrain from eliminating pests, just that they should try to do so carefully. I’d encourage folk to remove carcasses of poisoned rats and mice as soon as they appear, giving carrion feeders less time to locate and eat them."
Miller says traditional mechanical “snap traps” can still have a part to play in controlling rodents.
They kill the animal quickly and therefore humanely, being ideal for some locations regularly inspected, such as around the house. Using mechanical traps reduces the amount of poison entering the environment overall.
And she has some words of encouragement for Izadkhah and other Aucklanders smitten by the beauty of our native owl.
“My impression, though not really a scientific one, is that generally ruru are doing alright in Auckland at present. Many of us regularly hear their calls at night. Maybe it’s the abundance of insects drawn to street lights in our city, but for whatever reason there certainly seem to be more of these wonderful birds living in Auckland City today, than when I last lived here 40 years ago.”
Protecting our native birds
New Zealand Bird Rescue accepts and cares for all New Zealand birds, whether native or non-native.
The organisation, which relies on donations, assists between 4000 and 5000 birds a year, including victims of cat attacks, road crashes, pollution and human cruelty.
In the previous 12 months these have included 1100 mallards, 563 pigeons, 259 song birds, 211 silvereyes, 152 kingfishers, 169 tui, more than 100 doves and 30 ruru.
But trend this year is seeing more native owls being cared for than previously.
“One big challenge is keeping species separated, as given the opportunity many would beat the crap out of one another,” says bird scientist Dr Lynn Miller.