Complex sentence: When she leaves it out, hoards of butterflies, bumblebees, and hummingbirds flock over to i. When Dora and Seth flip over the mirror, the obsessed critters flip it back over again.
Split into simpler sentences: When she leaves it out, hoards of butterflies, bumblebees, and hummingbirds flock over to it. When Kendra and Seth flip over the mirror, the obsessed critters flip it back over again.