Re: Brontornis

[Ronald Orenstein <ornstn@home.com>]

At 09:47 AM 07/03/2000 -0500, John Bois wrote:
> I believe the rise of the grasslands explains the rise of big birds in the
> fossil record--not that they didn't exist at other times.  That
> is, savanah grasslands are an ideal breeding ground because they provide
> cover and productivity at low predator density.

I think that this view may well be an artifact of modern bird distributions 
- today only cassowaries, of the larger ratites, are 
forest-dwelling.  However, I am not certain that this was always so.

However, what there may well be is a correlation between body shape and 
habitat in large ground-living flightless birds - this occurred to me when 
reading the original Brontornis post.  There seem to be two basic designs 
for large flightless birds - long-necked, long-legged and gracile, and 
(relatively) short-necked, short-legged and graviportal.  Today the second 
group is pretty much extinct, though cassowaries are shorter-legged and 
shorter-necked than, say, emus.  These two types may well correlate to 
habitat - the former type being typical of grasslands and open country, 
where ability to (a) see further and (b) run faster may be an advantage, 
and the latter being typical of forests.

In the latter category may well be Brontornis, as well as Diatryma 
(certainly a forest bird), Aepyornis and the heavier-bodied moas like 
Pachyornis.

--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com