Hummingbird
Hummingbirds are birds native to the Americas and constitute the biological family Trochilidae. They are among the smallest of birds, most species measuring in length. Indeed, the smallest extant bird species is a hummingbird, the bee hummingbird weighing less than .
Dromornithidae
There are 7 species in Dromornithidae, the smallest species was "Barawertornis tedfordi", a bird about the size of a modern cassowary, weighing . The two species of "Ilbandornis" ("Ilbandornis lawsoni" and "Ilbandornis woodburnei") were larger birds, but had more slender legs than the other dromornithids and were similar to ostriches in their build and size. "Bullockornis planei" (the "demon duck of doom") and "Genyornis newtoni" (the "mihirung") were more heavily built, stood about tall and probably reached weights of . The largest dromornithids were "Dromornis australis" and the massive "Dromornis stirtoni" ("Stirton's thunderbird"). "Genyornis" is the best known genus.