Hummingbirds fly on their migratory paths from mid-morning ... There are even interactive maps online that can show you up-to-date data on where the birds are and in which direction they are moving.

On the slopes of a volcano in central Mexico, biologist Cuauhtémoc Sáenz-Romero and his team envision a climate refuge for oyamel fir trees and the monarch butterflies that depend on them.