What do you call a group of crows?

A group of crows is known as a Murder. (Don''t know why!)

If you've ever seen a group of crows it is quite a sinister sight. They look as if they are plotting something very dark like a murder, perhaps your own...

It is called a murder for two reasons. 1st if an injured strange crow finds its way into the territory of a familiar 'murder', that crow is likely to be killed or murdered; 2nd when a 'flock' is flying in a pattern they usually do so in a "W" shaped, thus the first letter of murder.

https://cbdteas.com/koglrl/what-is-a-group-of-crows-called

https://www.quora.com/Why-is-a-group-of-crows-called-a-murder

There are several different explanations for the origin of this term, mostly based on old folk tales and superstitions :
•For instance, there is a folktale that crows will gather and decide the capital fate of another crow.
•Many view the appearance of crows as an omen of death because ravens and crows are scavengers and are generally associated with dead bodies, battlefields, and cemeteries, and they’re thought to circle in large numbers above sites where animals or people are expected to soon die.
•But the term “murder of crows” mostly reflects a time when groupings of many animals had colorful and poetic names.

One explanation is because a group of crows will sometimes kill a dying crow.

http://www.woodswanderer.com/tag/crows/