"e. eocaenus" might have been a frugivore or even herbivore of swamp forests, but the early neoaves (to which it probably belonged) are generally predatory. as a predator, it would have fed mainly on mid-sized terrestrial vertebrates—for example large reptiles or smallish mammals. alternatively—depending on its preferred habitat—it could have eaten mainly aquatic vertebrates. it cannot be ruled out that it was a filter feeder like flamingos (as of 2008 tentatively considered highly specialized "higher waterbirds") or most anseriformes. in any case, it would need to roam a considerable range to find enough food, and thus population density was likely low. unmated birds were probably solitary. mated pairs might have stayed together for life, as they often do in birds.