And only the sky becomes a blue wing with a blue wave

Or this:

"Not for the blue bird,

I'm coming for you.

U - U - U - U

"Follow you like a blue bird"?

And also the All-Russian competition of young talents "Blue Bird", the Natalia Sats Theatre with its emblem - a blue bird, and even the first Soviet passenger plane was called "Blue Bird"!

The symbol is so ingrained that it seems it must have roots in the deep past, perhaps having a connection with mythology, with different cultures and languages...

In fact, it turns out that no - all the blue chicks have flown out of Maeterlinck's play! Before her, the blue bird was not a metaphor for happiness.

The play "The Blue Bird" by the Belgian playwright flew around the world very quickly and with great success a little over a hundred years ago. It is interesting that at first it was just a play, the text was reworked into a fairy tale later, and not by Maeterlinck himself, but by his wife.