Attached Link: http://rinkworks.com/words/collective.shtml

some of my favorites, (from the same book :-), are "a murder of crows", "ostentation of peacocks" & "a romp of otters". pigeons however have several collective descriptions including, flight, dropping, and yes flock :-) the link above is for a webpage with a representative listing of collective animal nouns for those of you who don't have the book :-)