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RE: BCF ANDPDW
On Tuesday, August 04, 1998 7:33 AM, Ronald Orenstein
> However, all these birds are large and may have been flighted until they
> reached a certain size (perhaps larger than the living Kori Bustard, with the
> Mute Swan the heaviest of flying birds today); penguins, steamer-ducks,
> flightless grebes and various extinct flightless waterfowl aside, I think it
> would be safe to say that all smaller flightless birds alive today (or in the
> recent historical past) probably evolved on islands.
Apologies if this has already been stated, but I thought secondary
flightlessness evolves where there is a lack of predation? Both island
isolation and large size (larger than any other animal that might be a threat,
anyway) could fit this description. Not sure if you were saying that large size
equals too much weight to fly (which I don't care to dispute), but maybe
Phorusrhacoids had no need to fly, because there was nobody else mean enough to
fly away from?