Together with her colleagues, ecologist De Jager conducted the research for the province of Friesland, which wanted to map the conflicts between farmers and geese. If groups of geese often move to other places, damage must also be assessed more often. There are also costs involved. The researchers put all these costs and the energy consumption of the geese into a computer model. This way they could calculate what is wisest. The calculations showed that chasing “makes sense if there are relatively few geese, but that it is better to let geese graze quietly, even outside the resting areas, if the population of geese increases”.