This video is called The Alcon Blue Butterfly.
From Belgian daily Het Laatste Nieuws:
Flanders now has considerably less butterflies.
Not just the number of species gets less, also the numbers of individuals of the various species get less.
However, measures to help the rare alcon blue butterfly do seem to be effective.
Also, in Vlaams-Brabant province, recently the sooty copper, thought to be extinct, was re-discovered. …
“Flanders once had 64 native butterfly species, of which a third has become extinct”, Wouter Vanreusel of Natuurpunt says.
Dingy skipper butterflies in Britain: here.