Re: ...bats by day, and bats, birds, by night.

["James R. Cunningham" <jrccea@bellsouth.net>]

John Bois wrote:

> Outside of catastrophies (which you're not invoking) competition and
> predation are the prime causes (most likely) of most extinctions.

For soaring animals, there is another, perhaps more likely, cause of selective
extinction which does not involve competition, predation, or food supply. You
might wish to consider it.

> I don't know why not.  List members have come to expect a gaffed detail such
> as this from me, just as they may learn to expect lack of civility from
> you.

Come on, fellas.  We all gaff a detail from time to time. And we all are
sometimes somewhat less than civil.

> > > for late K pterosaurs?  Remote nesting was probably the only available
> > > strategy for them. So...
> >
> > So what? Maybe that was just what they did. There always were islands, if
> > you want such extreme protection.
>
> But predator access to those islands has changed over time--with the
> evolution of new/different predators.

One of the nice things about being able to fly is the ability to move from
island to island.  It can allow one to leapfrog a few of the predators.  As an
aside, range tends to be unrelated to physical size in flying animals.

> 2) No pterosaurs handed over their niche as a gift to rising new species.
> 3) Something forced them out of their niche.
> 4) The most likely things to do this is are flying creatures.

2) true3) maybe
4) for soaring animals, there is another, possibly more likely cause.  If this
exchange were taking place in one of my classes, I'd suggest that everyone think
about it a bit and ask for a discussion of possible causes.  Come to think of
it, I believe I'll do just that.

> 5) The most likely flying things to do it were the only ones that
> existed--birds.

5)This presumes that 4) is true. 4) isn't necessarily true.  What might be some
of the other options?

> In any case, chances are that fossils will be informative (ultimately) of
> relative diversity and biogeography of these bird clades.  Let's just hold
> our fire till then.

Does this mean that we should not consider other possible causes for the demise
of some types of pterosaurs?  Causes which may have nothing to do with birds,
predation, or disease?  Why should we wait for more bird fossils before
considering other alternatives unrelated to birds?  Though those other
alternatives might also affect the evolution of birds, independently of
pterosaurs.