Answer:
It would cause a decrease in the carrying capacity of the owl population.
Step-by-step explanation:
The relationship between a predator and prey is unique. Both the population of a predator and prey gets affected if changes in one of them occur.
If mice migrated from the ecosystem, this will mean that there will b little food available for the owls on that ecosystem. As a result, they will compete for food. Some of them would get killed due to lack of food. Others will migrate to places where they can find food. Hence, the carrying capacity of the owl population would decrease.