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breeding, numbers, nesting, and flight



     OK,
     so everyone wants to know why dino-birds started to fly.  During the 
     current discussion, I was struck by the ideas that:
     
     1)birds tend to have low-numbered broods.  The evolution of flight was 
     always credited as the limiting factor.  However, dinosaurs seemed to 
     have a different breeding srategy-high number broods.  What if the 
     trait to have limited broods was evolved BEFORE flight, thus making it 
     more of each dino-bird's interest to rear and nurture their young into 
     adulthood?  The strategy-shift would seem to encourage finding better 
     hiding places for nests, and as far as I am aware, there are no 
     tree-nesting dinosaur sites.  So the dino-bird went into a 
     climbing-brachiating form for nest preservation.  Flight came after.  
     Grasping for branches came first.
     
     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.
     
     What do you think?
     
     -Betty