
A Thermodynamic Answer to Why Birds Migrate - zeristor
https://www.quantamagazine.org/a-thermodynamic-answer-to-why-birds-migrate-20180507/
======
zeristor
A curious point, energy is one thing but there needs to be the nutrients at
hand to capture the energy in the first place.

The Amazon jungle though does well with its furoius exosystem recycling all it
can, and seemingly dependent on wind blown sand from the Sahara to provide
some nutrients.

Could birds being so mobile could move nutrients around the world?

~~~
korethr
That's not a crazy idea; there are plants which rely on the mobility birds for
reproduction and spreading. Take peppers for example. The seed pods are
attractive to birds due to their bright colors. The capsaicin that deters many
insects and most mammals (except for us batshit-crazy humans who enjoy the
sensation of chemical warfare upon our tongues for some reason) can't be
tasted by birds. The seeds themselves are protected from the bird's digestive
tract by a membrane. Digestion softens said membrane enough to allow for easy
germination, and the ready-to-germinate seeds are then spread around the area
by the bird passing the seeds while in flight. And so the pepper plants
spread.

~~~
sliken
While humans like capsaicin, we can't stand nearly as much as birds can. Sure
people eat ghost papers and make amusing videos of themselves in pain. Birds
however aren't bothered by even 1% capsaicin by weight, far more than any
normal human would voluntarily consume.

~~~
korethr
Which was part of my point, above. Birds are incapable of tasting capsaicin at
all. So they'd have to be hit with a dose thereof unrealistically larger than
anything they'd ever encounter in their natural environment before it begins
to cause problems for them, and at that point, other compounds in the peppers
probably would've started causing problems long ago. And so, they happily eat
the tasty seed pods which the plant so helpfully color-coded as edible, and
then poop the seeds around their environment, thereby helping those tasty
plants become more numerous.

------
dryst
TLDR, birds have nothing to eat, and freeze to death if they stay in cold
weather for too long. They are mobile, and move to places where that is not
the case.

