Question

Explain what might happen to the fox and the hawk populations if a disease dramatically reduced the mouse population.

Answer 1

Nature survives on a thin equilibrium between the species that hunt and those that are hunted.

When one of these increases or decreases drastically, the other is also affected.

In this case, both hawk and fox hunt mouses. If there's no mouses both hawk and the fox will starve to death.

Answer 2

They may have a decline in population due to a reduction in available food.  They would focus more on the other prey.