When do monarch butterflies migrate? which of the following would be the feast

Explanation: they migrate around September when it starts to get chilly and they go west

The monarch migration usually starts in about October of each year, but can start earlier if the weather turns cold sooner than that. The monarch butterflies will spend their winter hibernation in Mexico and some parts of Southern California where it is warm all year long.

Explanation:

"the sandy walls seemed to collapse in on themselves"

and

"the bloodshot waters seemed to have no bottom"

the underlined phrase is an example of : understatment