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GO writes:

>Islands often occur _within_ continental land masses as well as offshore. The
>formation of an island could isolate a bird population from the rest of the
>continent, then, after the island rejoins the main land mass, the resulting
>flightless bird population would be released onto the mainland. I'm not
>saying this happened in every instance of evolution of large, flightless
>predatory birds, but it is at least plausible and may have operated in some

Maybe - but I do not think they are required for a bird already large and
fast-running.  Without direct evidence I will assume that these birds
evolved in areas with predators, but that their loss of flight aided
predator avoidance by permitting the evolution of larger size.
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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