Quoting "T. Michael Keesey" <keesey@gmail.com>:
Much more often among rails alone -- 2000 years ago, every small Pacific island had its own species of flightless rail, and the big ones had two or three, never mind the occasional flightless parrot or duck or ibis or...
Right, see, I knew I was missing some stuff (although I think I counted 1 for parrots and 1 for anserids).
On another note: is there a single instance in all of _Bilateria_ of a lineage losing flight and then regaining it? (Tinamous aside for the moment.)
Nick P.