This is the 534th most frequent Polish word.
tysiące
"Thousands."
In this sentence, 'tysiące' is used as a numeral form referring to a large quantity, specifically thousands of people, emphasizing the high attendance of the event.
Na koncercie było tysiące ludzi.
There were thousands of people at the concert.
Here, 'tysiące' indicates a vast amount of books someone possesses, highlighting abundance or exaggeration depending on context interpretation.
Mam tysiące książek w swojej bibliotece.
I have thousands of books in my library.
In this context, 'tysiące' represents the magnitude of birds in the scene, paired with 'setki' to express an even larger collective group.