Conditions for secondary flightlessness (was RE: Ruben Strikes Back...a long time ago)

["Larry Febo" <larryf@capital.net>]

NJPharris wrote (in response to DinoGeorge):

<<Date: Fri, 24 Sep 1999 15:58:44 EDT
From: NJPharris@aol.com
To: dinosaur@usc.edu
Subject: Re: Ruben Strikes Back
Message-ID: <29bab744.251d31f4@aol.com>

In a message dated 9/24/99 12:43:06 PM Pacific Daylight Time,
Dinogeorge@aol.com writes:

> Well, secondary flightlessness has occurred in dozens of modern avian
>  lineages independently and convergently.

Though most occurrences were under specialized conditions, esp. on islands
or
isolated continents.>>

My response: These specialized conditions seem to have been a lack of
predators on the ground, allowing the normal flighted species to "discard"
their abilities to escape by flight. Could have been on islands , but
perhaps....may have been after massive predator extinction events. IE after
bolide strikes or similar catastrophies that were only severe enough to
eliminate the extant large predator population. The top of the food chain is
, after all, also the most susceptable to enviornmental stresses. If there
were a regular occurrance of large bolide strikes, there must also have been
an even larger number of smaller hits, any one of which may have caused
periodic continent-wide extinction of the large predator population.....NO?