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Re: mammal mystery



At 09:12 PM 2/19/97 -0500, John Bois wrote:
>"...some fairly good-sized birds on islands like New Guinea and
>Tasmania..."  This is a relative dearth of flightless bipeds.  What do you
>suppose the ratio of quadrupedal lizards and mammals and snakes and flying
>birds is to flightless birds.  Very small.  My point is that species of
>this body plan are not very competitive in close cover.  I still think I'm
>right about that. 

Mr Bois, I am tired of repeating the same things over and over.  You are
NOT right about that.  Flightlessness doesn't enter into it when the birds
do not, as part of their daily activity, fly much or at all and there are
PLENTY of birds that compete perfectly well, thank you, on continents and
continental islands, as thicket skulkers or terrestrial stalkers in
forests.  Rails, pittas, antpittas, mesites, tapaculos, rail-babblers,
buttonquail, some partridges and true quail, trumpeters, etc etc etc!!!
Ratios have nothing to do with it either - if a reasonable number of these
birds survive well in areas where mammals and lizards also occur then it is
reasonable to conclude that they can get along in such environments.  By
your argument they ought to be tripping over themselves to such a degree
that there ought to be NONE in continental environments, and this patently
is not true.

 I think 2 legs is inefficient for running through
>tangled hoops.

Then why in the great screaming hell do so many birds do it so well????


  As you have noted I have little knowledge about rails.

Mr Bois, I really hate to say this, and I don't want to get personal, but
it truly seems to me that you have little knowledge of the natural history
of living animals in general, or that if you do you utterly refuse to
recognize it when it contradicts with your preconceived notions.

>The five species I have read about all seem to inhabit grassy environments
>which are relatively free of horizontal encumberances. 

There are MANY forest and thicket rails in the tropics of South America,
Africa and Indonesia.  You are undoubtedly reading about North American
species.  Read about the African flufftails of the genus Sarothrura,
Rallina forest rails of southeast Asia, and many others.

 Tell me two
>things: 1. How does a rail move through a hoop at full speed, like a
>spear? Try not to ridicule this point.  I honestly can't imagine such a
>creature out running a, say, rat in a close hooped environment

I can't really imagine why such a creature WOULD WANT TO "outrun" a rat,
and in fact in such dense environments both quadrupeds and bipeds are far
more likely to rely on staying still and avoiding being noticed than on
speed when it comes to avoiding predators.  Manoeuverability counts too.
Again you are ignoring the nature of these environments and the creatures
that live there.  Also, remember that most of the mammals involved here
would be nocturnal and the birds diurnal, so they probably wouldn't even
run into each other when both were active.

>       2. If bipedalism was no impediment to dinosaurs in close-cover,
>why do you think they were excluded?  (I believe we do see mammal
>replacement at least in this niche, no?)

Who says they were?  How do you know that there were no dinosaurs in such
environments?

>I appreciate your knowledge a great deal, and a great deal more than your
>manners.  Mine is a reasonable hypothesis whether or not you like it.

No, it isn't.  Rails are highly-adapted, successful birds found on every
continent but the Antarctic, with 143 extant species in 34 genera.  They
are superbly adapted for getting about in dense undergrowth - otherwise why
do you think they have survived at all?  I realize that my suggesting that
you lack the facts to back up your claims may seem impolite, but it is
highly frustrating to see you continuously make claims about the natural
history of living animals that have not the slightest basis in fact.
Whether you think rails are clumsy or not is irrelevant - anyone who has
spent any time with them (and there are some on this list besides me who
have) will tell you this is utter nonsense.

Here, for what I hope will be your edification, are a few quotes from the
highly-respected Handbook of the Birds of the World, Volume III:

"Rails often walk with strong, precise strides.  Being accustomed to cover,
they often move continuously without long pauses for visual orientation,
pausing mainly to feed.  When moving through low vegetation, they slip
beneath low horizontal stems or arched projecting roots, or raise the feet
high to step over such obstacles... In dense cover rails are adept at
walking, or even running, without causing any noise or movement of the
vegetation.  When reacting to alarm, they melt quietly and rapidly into
cover, often lowering the head and stretching out the neck, as they
compress the body to allow easy passage through the stems....

"The wide distribution of the family is a reflection of the ability of
rails to adapt to a very diverse range of habitat types.....  The ability
to capitalize on this great diversity of habitats throughout the world
indicates that the family shows great adaptive plasticity.... "

Not a word about awkwardness, falling over their own feet, etc. Okay?
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          Internet: ornstn@inforamp.net