This white tern is completely lethargic as it has been immobilized by the seeds of the Grand Devil’s-Claws (Pisonia grandis). The tree produces inconspicuous but sweet scented flowers and during the flowering one cannot see the sinister side to this species, as it is the seed that kills. As the seed develops you’ll see spikes grow, albeit soft during development, but when the seed is finished growing it will dry, and these incredibly tough spikes will be a killer by starvation for the birds.
The trees are important nesting and roosting grounds so they are irresistible. The “fee” for the services is the seed that will stick to the plumage until the feathers fall off. They stick so well to the feathers that it takes a lot of energy for a human to detangle and remove, but for a bird it is impossible to remove it. A single seed is perhaps not a problem, but as the bird unwittingly touches more, the plumage will be dotted with the seeds and eventually make it impossible to fly. Most of the seeds are still sitting on the inflorescence, and thus the bird will be dragged into a web of seeds, like this poor tern. The spikes are so hard that to touch a seed without gloves you risk deep skin punctures and lots of bleeding. This is how hellish this seed is. They also decompose much slower than the tree itself, so they will lay around on the ground throughout the year.
If you look closely underneath and around these trees you will see quite a few bird bones and skeletons from birds starved to death by these hellish seeds. It’s a rather strange evolutionary outcome, as these seeds have evolved to killing their disperser. Perhaps if the seed did come off more easily it would not have been able to travel throughout the Indian and Pacific oceans, and as such the species would not have been able to have such a wide range. Yet I wonder what the seed looked like when the species was at its infancy.
This tern was in luck as I was able to carefully remove every seed, but it was no simple task. I learned the hard way that putting pressure on these seeds will make your fingertips bleed.
It sounds like this:
Last updated on 20 October 2021
