Figure 10: Dependence of the population density at the end of the breeding period on the date of departure for autumn migration and on the length of the autumn stop-over period resulting from simulations. Due to shrinking resources in the breeding site, the best departure date is right after the end of the breeding season. The length of the stop-over period is not critical. All times are with respect to a year of length 1, starting at the shortest day of the year.