Butterflies are still struggling in the Netherlands, according to butterfly foundation Vlinderstichting's annual report. Half of the 47 species the foundation keeps track of is in decline. Since 1992, the number of butterflies in the country dropped by around 40 percent, ANP reports.
Volunteers keep track of butterfly populations on a weekly basis on hundreds of routes in the country. Their observations show that 2017 was a very good year for some species, but dramatic for others.