This is De Ganzenfanfare (The Geese Parade) and is a performance which is put on mainly in the Netherlands and Belgium. According to their website, the show has its origins in “the age-old tradition of goose herding”.
I am now disappointed in @chefpyro and @siebewastaken for never telling me about this sooner.
In my defence, I have never heard of this in my life.
(Source: http://chefpyro.tumblr.com/)