Oxford's guide to collective terms for animals
is a useful and fascinating although all-too-brief resource. Collective terms for birds are some of my favourites: an unkindness of ravens; a murmuration of starlings; a richness of martens. Bees and sheep seem to have a lot of collective terms. I can't imagine why. Altogether, though, I found one of the terms for for ferrets to be the pick of the bunch.