In a similar vein, this rumination on a simple ecosystem involving seabirds, ursines and baked goods is widely (but not universally) attributed to Christopher Isherwood.
The common cormorant or shag
Lays eggs inside a paper bag
The reason you will see no doubt
It is to keep the lightning out
But what these unobservant birds
Have never noticed is that herds
Of wandering bears may come with buns
And steal the bags to hold the crumbs.