This is a Dutch video about butterflies.
25 years ago, in the Netherlands, the Nederlandse Vlindermeetnet was founded, an organisation for butterfly research.
Millions of butterflies have been counted in those years. Including meadow brown, the most often seen species: 954,959 individuals.
Since 25 years ago, 18 species have increased, 9 species are stable, 24 species have declined.
Speckled wood have increased, especially since 2000, both at places where they already lived and at new places.
Arctic skippers have increased too, but only at places were the species already occurred.
Among the butterfly species which have declined most are large chequered skipper and tree grayling; both with a decline of over 90%.