by Allie Mazzella
This month, I am taking a vacation, and recent Brandeis graduate Allie Mazzella tells us about her trip to New Zealand and the strange birds she saw there.
After graduating from Brandeis University, I decided to get as far away as possible—New Zealand. I was there for three weeks, and everything about it was wonderful and alluring. Because it’s an isolated island, New Zealand is an evolutionary playground, with innumerable plants and animals taking unique evolutionary paths. It’s also a hotspot for endemic species – organisms that cannot be found anywhere else in the world. I saw all the species commonly discussed in biology textbooks, a dream come true for a nerd like me. And yet for all of the beauty I witnessed, my favorite moment of the entire trip was when my friend and I were attacked by birds.
Kea birds to be exact.
The Kea is the world’s only alpine parrot, most commonly found amidst snowy mountains and endemic to the South Island of New Zealand. Keas travel in groups, have beautiful green plumage, and actually appear very friendly. At first.
Then the second. Then the third. And then we lost count because one started eating our windshield wiper, another started pecking at our tire, and a third flew up and started clawing on our passenger window! Much screaming occurred.
Afterwards, I could not stop thinking about the Keas. Not how terrifying the incident was, but how impressive it was. A truly organized attacked, like a pack of wolves. And yet, why would such a smart group of birds think eating rubber was a good idea?
Kea behavior has been intensely studied since the early nineteenth century, a favorite subject of naturalist Alfred Russel Wallace. It turns out that Kea birds are both the world’s only alpine parrot, and the world’s only carnivorous parrot. These two characteristics go hand-in-hand; there aren’t very many vegetarian options during the snowy winters, so the Kea adapted.
What makes this so interesting is the timing, motivation, and perception of the Kea’s carnivorous habits. The jump from fruit-eating to meat-eating was sudden, and discovered in the late 1800s when the Kea were found eating sheep. Not just eating, but killing sheep—causing sores to emerge and then repeatedly pecking at them until the sheep died, at which point the birds would then start tearing at the flesh.
The Kea’s anatomy is well adapted for this seemingly bizarre behavior. Although they have the distinctive claws of a parrot, they have a beak structure similar to that of a hawk. This makes it easy for the birds to tear at flesh while still having a firm grasp on the animal. This is also how it was so easy for the birds to start attacking our car. Additionally, the birds always work as a coordinated team, which usually consists of 4-6 birds attacking a single prey at a time.
Because sheep were and still are extremely valuable to New Zealand, news of the attacks spread wildly. There were reports of the birds killing up to 200 sheep in a single night, and up to 150,000 sheep in a single season. This led to the Kea being extensively hunted throughout New Zealand. Once one of the most common birds in the South Island, Keas now number only around 3,000 in total.
Initially, this organized sheep-attacking behavior was regarded as malicious and menacing. Some scientists even called it psychopathic. The reasons behind the change in Kea behavior were heavily researched, with scientists initially believing that a genetic or environmental change had altered Kea mindsets.
Then it was hypothesized that the birds were actually just doing what they had to do to survive the cold harsh winters. Or maybe the Keas ate the sheep by accident, thinking the wool was a plant and then eating it (this is called the vegetable sheep theory). Kea evolutionary history was also investigated. But now, researchers have arrived at the best conclusion ever: The Kea did it for fun.
Not psychopathic fun, but a true love for amusement, displays of cleverness, and a hint of mischievousness. Although the Keas were selectively pressured into eating meat, they were just doing it in style. And they most likely picked sheep as a meat source because they were attracted to the idea of playing with “woolly toys.”
This hypothesis also explains why the Kea started attacking our car. Not attacking, rather trying to have some fun. The Kea are now regarded as the “clown of the mountains,” and as a treasure, rather than a menace. However, there are signs everywhere telling you NOT to feed them.
The story of the Kea birds reminded me that there isn’t always a nuanced explanation for everything in nature. We are taught as scientists to assume the simplest explanation until proven wrong, “if you hear hoof beats, think horses not zebras.” But sometimes zebras prevail over horses, because zebras are striped, cool, and more fun.
It’s also important to constantly poke at questions we think we have already answered. There is often much more to learn.
Finally, science is awesome. I was a little burnt out from science after graduating from college, but this reminded me why I love it: the beauty, the serenity, the insanity, the fascination, and of course the terrifying fun. Out of the classroom setting, it was amazing to see nature in action, and to get to be naturally curious about the Keas. The world is a crazy place, and it’s important to remember to be a birdbrain, get out there, and have fun.
© Science Whys, 2016