Something other to add into the modeling. If you assume no successful reproduction, know the ages of the females, the age at which they cease breeding, and mortality rates you can figure when things have to change by. Say the youngest female is 10, females stop breeding at 40 then we have 30 years to get things fixed. Not 100, but 30.

Any reasonably good population dynamics person should already have this fissured out for the SRKW as the worst case.