Why do magpies swoop? A bird’s eye view on avian attacks

Tuesday 11 October 2016

A bike is the size of a large threatening mammal—well, it is a large threatening mammal—and moving quite quickly, and something moving quickly might often be a predator

Any cyclist with a passing familiarity with the science precinct at ANU would know about The Magpies of Linnaeus Way. They are so famous that they even get capital letters, as all celebrities should.

“They’re very impressive birds. They’ve got a big presence,” says their spokesperson, Professor Robert Magrath from the ANU Research School of Biology, an expert on avian social behaviour.

And for about five weeks from the beginning of September every year, they make their “big presence” felt on the heads of any passing cyclist, the reason for their fame.

“Someone can go past on foot and they’ll be completely ignored, and someone will come down on a bike and they’ll get the full fury of the local group of magpies,” Professor Magrath observes.

So why do they pick on cyclists specifically?

“A bike is the size of a large threatening mammal—well, it is a large threatening mammal—and moving quite quickly, and something moving quickly might often be a predator,” Professor Magrath explains.

“The magpies perceive that there’s threat to their chicks and they respond aggressively to that threat.”

So it’s a case of taking helicopter parenting a bit too literally.

But why, since cyclists don’t tend to ride their bikes up trees and steal magpie chicks, do magpies feel the need to be so defensive around a threat that has never, ever actually eventuated? Turns out they’re in too deep to stop.

“If you put yourself inside the mind of a male magpie, a fast-moving large predator comes in their territory, they dive-bomb and it goes away so they’re very successful. And each year the same thing happens and they successfully drive away dozens of bicycles every year so in that sense there’s no particular reason for them to think it’s an unsuccessful strategy.”

Professor Magrath’s advice is not to take it personally.

“Just recognise that the magpies are just protecting their family basically. They’re not evil in any sense. They’re doing exactly what humans would do. If you perceived a threat to your children, you would behave in a way to chase the threat off.”

He also says the cyclists of Linnaeus Way should count themselves lucky.

“Swooping from behind is a relatively safe form of attack. There is a very rare type of magpie, maybe one in 100 attacking magpies, that will go for a full-frontal attack. They’ll actually land on the ground in front of you, look you in the eye, and attack you in the face. Apparently it’s absolutely terrifying and really quite dangerous.”

Given the thankfully less bloodthirsty proclivities of The Magpies of Linnaeus Way, there’s an easy solution for the cyclist who doesn’t appreciate their attention.

“One trick is simply to get off your bike and there’s a good chance the magpie will stop attacking you.”

Easier said than done, though, under a barrage of beaks and flapping wings.

“It is,” Professor Magrath laughs. “I usually ignore my advice and just pedal faster.”

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