> First of all, tinamous ARE ratites despite their size and flying
> ability, so there is no reason to assume that their brooding habits
> were independently acquired.
I was not aware of that. When you say ARE, which phylogentic
hypothesis/taxonomy are you referring to? Tinamous are usually
classified in their own Order, Tinamiformes, distinct from the
Ratitae, aren't they? Hackett et al. (Science 320 (2008) did nest
tinamous within the "Struthioniformes", but they refer to the
Paleognathae as "ratites and tinamous". Other phylogenies, such as
Dyke & Van Tuinen, Zoological Journal of the Linnean Society 141
(2004), found tinamous to be more primitive than any ratite.