This Mysterious Tree Appears to Kill Birds Just For The Heck of It (ScienceAlert)
MIKE MCRAE
20 JAN 2018
It's not unusual for plants to stick, prick, or entangle their seeds into some hapless animal that steps too close in search of a meal or a place to rest.
But one genus of tree found in the tropical waters of the Indian and Pacific oceans has taken this method of distributing its seeds a little too far, killing many of the birds that land in its branches by weighing them down and preventing them from flying away.
The thing is, there doesn't seem to be a clear reason for this wanton slaughter, leading one ecologist to suggest that it's just one of those macabre quirks of evolution.
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What sets the Pisonia apart from other trees that use glue or prickles to hitch a ride is that these seeds can pile up rather quickly – especially if a bird falls or lands among the pods on the ground – weighing down smaller individuals and making it impossible for them to fly.
If they're not picked off by a passing scavenger or predator, most birds die and decompose at the foot of the tree. Some poor victims can sometimes be seen still stuck high in the branches, as Jason Bittel at The Washington Post so colourfully puts it, "like macabre Christmas tree ornaments".
https://www.washingtonpost.com/video/c/embed/ea7ab2fc-14b6-11e7-bb16-269934184168
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more: https://www.sciencealert.com/this-tree-seems-to-kill-birds-just-for-the-heck-of-it?perpetual=yes&limitstart=1
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