Christopher Taylor
In all the studies I've seen more recently (both morphological and better molecular methods), _Anseranas_ has returned to its position as next basalmost living anseriform after screamers. Still, _Anseranas_ is a lot more reminiscent of a screamer ecologically than any other Anatidae s.l.
In relation to dromornithids, analogy with other living anseriforms/ Galloanserae would suggest a largely omnivorous diet - primarily vegetable matter, but a reasonable amount of animal food where available.
*My comments on the unreliability of DNA-DNA hybridisation are in no way a condemnation of Sibley et al. for using them. Molecular methods of looking at relationships were still in a very primitive state, and hybridisation was probably just as good as any other technique available at the time.
Cheers
Tim