Re: Archaeopteryx with bird book, was Re: Archaeopteryx flight

[Patrick Norton <ptnorton@suscom-maine.net>]

> > A naked head is also useful for scavenging -
> > prevents fouling of the plumage
> > while the scavenger is immersing itself in a rotting
> > carcass.  I'm not
> > saying that _Archaeopteryx_ was a scavenger - but
> > the head (and neck) may be
> > naked for purposes other than display.
>
> In total, maybe 1% of living birds have bald heads.
> Scavenging birds are much bigger than A., possibly
> because carrion is scarce resource and they need
> passive flight to cover vast areas to locate it.

Where is the evidence of selection for baldness in scavenging birds?  Other 
than vultures, I can't think of any other type of scavenging bird that is 
bald (crows, ravens, magpies, gulls as well as some types of owls, herons 
and raptors). And several of these types of scavenging birds are not much 
bigger than Archie. The absence of head feathers in Archie is far more 
likely an artifact of preservation than evidence of baldness. Flight 
feathers, which are anchored to bone, are more likely to remain affixed 
during preservation than contour feathers.

PTN