A large gathering of crows is, in fact, referred to as a murder.
So not necessarily a reference to the books.

As much as I like GRRM, it's not.

The collective term for crows is actually "murder." There are actually a whole bunch of these poetic collectives for animals in the English language, going back to the days when lords or other wealthy people employed gamesmen, hunters who were responsible for maintaining game--animals that weren't suited for domestication--on their masters' lands. The collective term for these collective terms is "terms of venery," venery being an archaic term for hunting.

Why this happened isn't exactly clear, and how widespread it was isn't clear either. But they got written down in a book in the 1400s, when rich folks started hunting as a pastime (some may have been commonly used, other were probably rare, and other probably made up). And--as so often happens--because someone wrote it down in a book, others accepted it without further question and insisted that "these are the proper terms." And so they survive on the fringes of the English language as this weird but fun artifact.

Examples:
A murder of crows
A crash of rhinos
An exaltation of larks
A gaggle of geese ( on the ground)
A skein of geese (in flight)
A sloth (sometimes sleuth) of bears
A business of ferrets
A tower of giraffes
A pride of lions
A skulk of foxes
An ostentation of peacocks
A parliament of owls/rooks

Fun fact: "venery" is also the noun form of the adjective "venereal." While the homonym is completely accidental (this other use comes from the Roman goddess Venus), it does leave Blizz with the option of adding "Venereal Diseases" to the Hunter toolbox. ("Toolbox," heh. I'm on a roll!)

Very well then, point conceeded.

I do reserve the right to carry with my faintly Medievel English accent though !

"carry on" even !