Insectivorous birds are birds that have a diet where their primary food source is insects. In the fall and winter months in the Northeast region, the temperature starts to drop and insects become scarce. What happens to the carrying capacity for insectivorous birds in winter in a northern New York forest?

It stays constant, since carrying capacity is a fixed value that does not change.
It quickly drops to zero once the temperature goes below freezing.
It slightly fluctuates above and below the optimum level.
It rapidly increases during the winter.

The carrying capacity for insectivorous birds in a northern New York forest would slightly fluctuate above and below the optimum level in the winter months.