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Re: Science feather strength debate



On 11/15/2010 7:31 PM, Scott Hartman wrote:
Heh, people can "refudiate" me all they want, but let's be clear what
that implies:

1) 10 specimens, most with at least faint feather impressions, several
with excellent and easily seen impressions, all with the flight
feathers ending in the same location at the elbow (i.e. no variation
in the end point that would imply randomness or missing elements)

Note -- I have had no opportunity to examine the fossils, and lack the expertise to draw conclusions from them anyway. My comments are based solely on personal observation of extant animals, living and dead.

The feathers ending at a consistent point does exclude randomness, but a preservational explanation need not be random. I have cleaned a lot of dove, bobwhite, some grouse, chickens, duck, geese and turkey. Humeral feathers can be removed w/ one or two swipes of the hand, even on the larger birds. The more outboard wing feathers, all of them, are *much* harder to remove. So hard, it is usual to cut the entire wing at the distal end of the humerus.

As birds decay, humeral feathers just fall out -- primaries can hold on even after all soft parts have disappeared, and the feathers covering them have scattered to the winds.

2) An exceedingly low-energy depositional environment (i.e. no
plausible environmental mechanism for removing the tertials),

Humerals float well to use as "fishing corks" when angling for small fish, due to the hollow nature and relatively large size of the base -- they have strong positive buoyancy even when soaked. If released from the body prior to covering by sediment, they would float to the surface like so many little lost souls ascending to the heavens.

Down feathers, not so much, due to more or less solid rachis. At least, they look solid to me. This could tested, minus the souls and heavens part, by immersing dead birds in still water. And monitoring the results over time. I am more than a little surprised this has not been done.

corroborated in the best preserved specimens as there's no evidence of
any displacement to the other feathers of the arm and tail.

3) In the Thermopolis specimen there is dino-fuzz preserved...which
presumably wouldn't be more durably attached than tertials.

I am not sure about that -- down is not dinofuzz, I guess, but can be surprisingly hard to pluck. But again -- is down buoyant when soaked in water? IIRC, no...