Q: Do you know why a group of crows is called a murder of crows? I’m a reference librarian and a patron asked me this. I couldn’t find the answer, though I did find a reference to the term.
A: The phrase “a murder of crows” is a poetic term, not a scientific one. The more common expression is “a flock of crows.”
The poetic version is one of the whimsical names for congregations of animals that can be found in James Lipton’s book An Exaltation of Larks. Other collective terms include “a covey of partridges,” “a rafter of turkeys,” “a brood of hens,” “a fall of woodcocks,” and “a wedge of swans.”
Lipton traces “a murder of crows” back to the 15th-century phrases a “mursher of crowys” and a “murther of crowes.” I’ve found postings online mentioning similar citations in the Oxford English Dictionary, but I couldn’t find such references in my CD-ROM version of the OED.
I’ve seen speculation on the Internet that the expression is based on a spurious folk belief that flocks of crows hold trials and execute (that is, murder) members for bad behavior. I’ve also read online that crows sometimes feed on the carcasses of dead crows and may occasionally kill a crow from another flock. I can’t vouch for either of these explanations.