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Re:Feathers for brooding, (was: So here it is... my paper...)



Did I hear my name mentioned?

<<What I do question is the idea that feathers were first developed for the 
purpose of incubating a brood. I know this is a fairly wideheld opinion.>>

Har! I am glad to see the speed with which the community has gone from deep 
skepticism to warm reception -- if true.

<<I believe I last heard it express on one of Paul Serenos websites, how 
"ideal" was the wing of Caudipteryx for incubating a nest>>

Did he reference us? Ha ha.

<<What I can`t see is why the feathers had to be arranged in such a neat 
linear fashion for insulating a nest. I can, however, see it as necessary for 
flight function which requires such prescision alignment to produce an 
overall aerodynamic shape to the wing, in this case, a strong indication of 
secondary flightlessness in Caudipteryx.>>

If you could read our Dinofest 98 paper (Don Wolberg, where are you?) perhaps 
you'd see. Mark Orsen and I went into much detail. Regarding your 
reservation, above, most logical would be the need to fold and fan a "move
able nest" as Mark likes to say. We have a series of photos showing a mother 
duck who has been brooding her babies under her wings overnight. When she 
stands, the babies are actually STANDING on her primaries. The evolutionary 
pressures on this foldable structure were, and are, intense. This, we think, 
drove the shape-development of the feathers, while the opportunity to care 
for larger broods drove their lengthening.

<<It seems to me that for the purpose of incubating a nest, a random 
arrangement of more plumulus feathery structures would suffice.>>

If you are ostrich-size, perhaps. But Microraptor-size? A strong wind would 
blow you away. Better hold those feathers in tight beside you. Watch out! A 
predator snapping at you. Too bad if your brooding feathers get you 
apprehended. Best to tuck them away. Moving through thick brush? What's the 
word for "brush-odynamic?"

Mark and I believe that the debate on flight origins has given too much 
emphasis to locomotion, and too little on all the other selective pressures 
birds have on their wing feathers.

I hate to be a name dropper but at Dinofest 98, after my talk, John Ostrom 
came straight out of the audience and shook my hand. He said, "Thank you. You 
have filled the last hole in my argument."

One more thing, despairing of Don Wolberg ever publishing our first paper, 
Mark and I are finishing a second, which restates and adds to our original 
presentation at Dinofest. Anyone want to suggest an appropriate journal for a 
hypothetical paper on the origins of brooding and birds?


<<After that, some tetanuran invented lying on its eggs and holding them with 
its arms. The arms of the famous brooding Oviraptor and ?Ingenia skeletons 
all circle the eggs in a way that if they had borne wing feathers, they had 
covered the nests and shielded them from sun and rain (Hecht, 1998 <yes, HP 
Jeff Hecht who mentioned this hypothesis by HP Tom Hopp in New Scientist>). 
Apparently there was a strictly Darwinian advantage in lengthening the arms 
and the feathers: longer arms = more wing area = bigger nests = room for more 
eggs = more offspring.">>

     
Thanks, David, for a very nicely encapsulated restatement of our idea. Glad 
to see someone gets it.

    

<<I would argue that the requirement for a "larger nest" and hence room for 
"more eggs and potential offspring" would be more appropriate for a species 
that did >NOT< carefully brood and care for it`s young. A species that took 
the extra time to brood it`s young, would also tend to provide ample care and 
protection against predation, thereby necessitating >fewer eggs< and 
offspring, and in fact would not be able to provide such care for an 
excessive number of offspring!>>

These are the r- and K-strategies for brood size discussed extensively in 
Dinosaur Eggs and Babies. There are reasons for both strategies to apply to 
dinosaurs.

Tom Hopp