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linked to human hunting, alterations of dromornithid habitats, or climate change.
But die out they did.
Othercolossalflightlessbirdsmanagedtoevolveonislandsmuchsmallerthan
Australiaandwellintothetimeofhumans.Forexample,theelephantbirdsofMad-
agascar, which consisted of species of
Aepyornis
and
Mullerornis
, were as much as
3 m (10 ft) tall and weighed about 400 kg (nearly 900 lbs). These herbivorous birds
evolved to great sizes while isolated from the rest of Africa, and until about a thou-
sand years ago the only primates they had encountered were lemurs. Sadly, all ele-
phantbirdswereextinctbytheendofthe18thcentury,likelyvictimsofadisastrous
blend of human-introduced avian diseases, too-rapid changes to their ecosystems,
and hunting. Surely another factor was that their eggs were hard to ignore for any-
one tempted by so much easily obtained protein in one place, as these were about
150times morevoluminous thanthose ofchickens. Almost nothingisknownabout
their nests, but they definitely were not located in trees, which left their eggs quite
vulnerable to any creatures with opposable thumbs that were able to easily carry
them away.
Until just recently—that is, in historical times—hefty birds also lived on New
Caledonia,Malta,Cuba,theHawaiianIslands,andanislandoftheFijiarchipelago.
New Caledonia, a Pacific island with a main landmass that was connected to Aus-
traliaandNewZealandduringtheMesozoic,hadboth
Sylviornis neocaledoniae
—a
galliform bird, related to chickens, turkeys, and other ground-dwelling fowl, but
standing 1.5 m (5 ft) tall and weighing about 25 kg (55 lbs)—and
Megapodius mol-
istructor
, a megapode (“large footed” bird) that weighed about 3 kg (6.6 lbs), three
times larger than any living megapode. Both birds were likely mound nesters, and
fortunately some trace evidence supported this idea. Archaeologists at first thought
hugeearthenmoundsonNewCaledonia—measuringasmuchas40m(130ft)wide
and 5 m (16 ft) tall—were human burial grounds, similar to those made by Native
Americans. The problem with this hypothesis wasthat the moundslacked anessen-
tialcomponentofhumanburialgrounds:bonesandartifacts.Thisiswhenscientists
