Re: breeding, numbers, nesting, and flight

[Jeffrey Martz <martz@holly.ColoState.EDU>]

>      2)Feathers evolved as a breeding aid-partially for display and 
>      partially to incubate broods.  Thus they didn't have to directly 
>      evolve for flight, but are awful handy as an incubator and heat 
>      retainer for something that hasn't grown it's feathers yet.  The 
>      barbels are great for retaining heat.

     The problem with this is that feathers are designed to keep the 
feathered animals body heat trapped in, so contrary to HELPING 
incubation, they actually hinder.  (Some?) birds develop a bare spot 
of skin with increased vascularzation called a brood patch (with the help 
of the hormones progesterone and prolactin, if you care) to allow body 
heat to escape and incubate the eggs.

LN Jeff