Where did "a storytelling of crows" and "a storytelling of ravens" originate?

From what i can gather from a few sources (not the most reliable however) these 2 collective nouns originate from folklore. The tale goes that crows and raven used to band together to form a kind of court to punish bad behaviour of another member of their flock. If they were proven guilty by the rest of the flock then they would be killed (or murdered) and this is where the collective noun 'murder of crows' originated.

http://wiki.answers.com/Q/What_is_a_group_of_crows_called

This link has a little at the bottom that may be of use:
http://www.pbs.org/wnet/nature/episodes/a-murder-of-crows/crow-facts/5965/