Last week Jesse Mulligan got an email from a listener, Richard Till.
"I'm unsure", he wrote, "of how to feel about magpies. I grew up loving the sound of them. I know the Dennis Glover poem, know the stories about how territorial they are and the hilarity than ensues.
"In the last couple of years there's been an explosion in the population of them on Banks Peninsula.
Magpie Photo: CC BY-SA 4.0 via Wikimedia Commons
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"At a recent social gathering I was bailed up by a belligerently drunk friend who, apropos of nothing, started telling me I should shoot all bloody magpies. She said they kill other birds in the nest. Bloody terrible birds, she said.
"So how DO we feel about magpies? Cheerful summer songbirds or enemies of the native birdlife? Can you get someone who knows on please? To be clear it's not because I want to shoot anything."
The afternoon team obliged and got Rebecca Stirnemann, central North Island manager for Forest & Bird, in to talk all things magpie.
Magpies, which were introduced from Australia in the 19th century, are very intelligent birds, she says.
“They're an amazing species because they're so intelligent. For instance, they can learn to recognize faces, and if you pee them off and mess with their nest, years later, they can recognize a face and get revenge.”
So, are these grudge-bearing birds really a problem? Not compared with other introduced pests, she says.
“They are nest predators, so they do predate other bird’s nests, but there has been some research looking at that and they found that in fact, rats and cats, possums and hedgehogs are all significantly worse, and are a much more serious pest, if you're actually looking to increase your bird numbers.”
So although a pest they are not our worst problem, she says, and they tend to stay in open farmland, native forests are not a natural habitat for them.
“I haven't heard of any research which says that numbers are significantly increasing, but it would be interesting to look at that.
“Mostly they do stay in open pasture land, which is their native Australian habitat. So, it's actually quite rare to find them in a forest, decent sized forest, or bush.
“Maybe in a remnant forest they might have more of an impact, but luckily, our native forest isn't as attractive to them because it's less like the Australian bush.”
Magpies are scavengers, she says.
“They eat pretty much everything. They eat insects and they'll eat fruit and yeah, and like actually a lot of different bird species if they can, they will have an egg or a fresh chick.
“And even some of our native birds like cuckoos do that as well. So, birds are somewhat adapted to nest predation.
“It’s just high nest predation by species like rats, cats, possums and hedgehogs, which are really leading to the decline. But of course, the magpie could be contributing somewhat to that, they're just not that big, the big enemy.”
As to whether numbers are increasing, it could just be that these feisty birds are very visible, she says.
“It can look like an explosion and they are really obvious birds, they're quite vocal and black and white and quite large so it could seem that there might be more when it's maybe just a little increase in numbers.”
If Richard wants to do his bit for native birds, stick to taking out rats, feral cats, possums and hedgehogs, she says.