This 25 December 2017 video is about frog species living in the Netherlands. Mainly edible frogs; also a tree frog and an European toad.
The piano music in this video is the tune of the old Dutch children’s song Er zaten zeven kikkertjes al in een boerensloot (There were seven little frogs in a farmer’s ditch). The ditch in the song is frozen, the frogs half dead.
According to Dutch Wikipedia, the song is from 1843.
However, it may be even older. I remember a version of the song with as final lines:
En er kwam een vent uit Pruisen
met honderdduizend man.
Die nam de zeven kikkertjes
en braadde ze in de pan.
A guy from Prussia came
with a hundred thousand men.
He took the seven little frogs
and fried them in the pan.
This may mean that the song is from shortly after 1787. Then, the king of Prussia had one of his generals invade the Dutch republic. Not with 100,000 soldiers; with 26,000 soldiers, but it was enough for victory. The aim of the Prussian invasion was to restore the power of Prince William V of the Orange dynasty, who had been driven away from the capital The Hague by the republican Patriot party.
The song may have been meant originally by the pro-Orange dynasty party to mock their Patriot opponents as powerless frogs.