Dairy farmers in Friesland and the Alblasserwaard are dealing with millions of mice that have damaged grassland and eaten crops such as carrots. The outbreaks, which had been more common until the 1950s but had not occurred for decades, are being investigated because it is unclear why they have returned and why they are concentrated in some areas.

In the Alblasserwaard, where the mice appeared for the first time this year, dairy farmer Mathijs Baan and Wageningen University researcher Gerbert Roerink discussed the outbreaks and ways farmers might protect their grass. Some aspects of the mouse plagues remain unknown.