Plants

The Pisonia Tree Lures and Murders Birds for No Good Reason

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Just because you can doesn't mean you should. Someone should tell that to the Pisonia tree, a savage plant that kills birds just for the fun of it. You may be asking, "Why?" Well, the tree would respond, "Why not?"

Oh Murder Tree, Oh Murder Tree!

If you didn't think a plant — a tree, no less — could be a jerk, think again. Found in the tropical waters of the Indian and Pacific oceans, the Pisonia tree fits the bill as one of the most unnecessarily cruel plants out there. While it's not uncommon for plants to have built-in defense mechanisms, those things are usually there to keep the plant safe. But scientists have yet to uncover any benefit the Pisonia tree could possibly receive for luring birds in only to murder them.

Here's what happens at the crime scene: the Pisonia tree produces sticky seedpods that trap insects, luring in hungry birds with the promise of an easy lunch. These seedpods are so sticky that they'll latch onto any bird that flies into them, either trapping it in the tree's branches or weighing the bird down so much that it's completely unable to fly. As a result, you'll see a spread of bird carcasses littering the roots of the Pisonia tree. There are sometimes even mummified bird corpses up in the branches that look like, as Washington Post describes them, "macabre Christmas tree ornaments."

Noddy Tern covered in pisonia seeds

I'm Tellin' Ya'll, It's Sabotage

Ecologist Alan Burger at the University of Victoria first heard of the Pisonia in the 1990s and went to the archipelago of Seychelles in the Indian Ocean to figure out why these slaughterous trees seemed to kill just for the heck of it. Until then, no one had looked too hard into the Pisonia tree, but there were two main theories as to why they were bird-tormentors: either the tree's roots got a nutrient bump from the dead birds, or the seeds attached to the dead birds because they required the corpse as fertilizer in order to grow. After 10 months of research with the Pisonia seeds, Burger published his findings in 2005.

The conclusion? Pisonia trees are straight ruthless. "The results from my experiments showed quite convincingly that the Pisonia derived no obvious benefit from fatally entangling birds," writes Burger. But not only did dead birds not benefit the tree in any way, but the poop of living birds would also help the trees survive by enriching the soil. It turns out, then, that killing birds isn't necessarily the goal. Birds flying away from the tree with sticky seeds attached helps keep the tree species alive by spreading the seeds far and wide. It's just one of those evolutionary whoopsies that the seeds sprout in clusters — heavy, self-sabotaging, bird-murdering clusters.

Curious for more of nature's killers? Check out "Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities." The audiobook is free with a trial of Audible. We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.

Written by Joanie Faletto June 11, 2018

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