At Summer Breeding Grounds, Insects Provide Food for a Migratory

At summer breeding grounds, insects provide food for a migratory bird species. Climate change could disrupt bird migration by affecting which factor?

A) the fact that birds migrate according to the sun's location
B) the fact that birds are the primary predators of insects
C) the fact that insects emerge from hibernation in spring and summer
D) the fact that insects feed on native plant populations