I didn't saw it at the first sign, but my son told me, it looks like a flying duck.

As a sign for all the wild birds coming from Africa with or without the bird flu.
And for all the chickens, the goose, the ducks and a lot of other birds
who have to stay inside in order of the government.
Hope it helps and we don’t get the disaster of a couple of years ago,
when a lot of Dutch chickens were killed.