Re: Hadrosaur nesting strategy...(was Re: The Life of Birds

[B.Dol@skn.sc.philips.com]

> Date:          Wed, 28 Jul 1999 11:48:07 -0400
> Reply-to:      larryf@capital.net
> From:          "Larry Febo" <larryf@capital.net>
> To:            <B.Dol@skn.sc.philips.com>
> Cc:            <dinosaur@usc.edu>
> Subject:       Re: Hadrosaur nesting strategy...(was Re: The Life of Birds- Pa

> 
> ----- Original Message -----
> From: <B.Dol@skn.sc.philips.com>
> To: <larryf@capital.net>
> Cc: <dinosaur@usc.edu>
> Sent: Wednesday, July 28, 1999 10:19 AM
> Subject: Re: Hadrosaur nesting strategy...(was Re: The Life of Birds- Pa
> 
> 
> > So wouldn't it be more logical to assume that the reasons for
> > migration are not avoiding predators, because in another area there
> > will always be other predators...maybe not that many or directly
> > threatening, but they could in time evolve that way.
> > Just a thought.
> >
> 
> I don`t know for sure. The avoidance of predation upon the young I had once
> read,...somewhere (can`t remember where). Sounded like a good, logical
> reason  to me. It`s amazing how much evolution revolves around raising up a
> new brood. That`s the definition of biological fitness,...the number of
> offspring that survive to reproduce on their own.
> 
> It was suggested to me (offlist) that more abundance of food was the reason
> for bird migration. I thought food was always much more abundant in the
> tropics, and therefore the ability to brood in a colder enviorn as
> protection from cold-blooded predators would be the determining factor in
> bird migration. Then again, not all birds migrate. How do the tropical
> variety cope (with predators)?

I'm not sure. 
Maybe because of the tropics more food is available so 
more offspring can be produced to ensure the species survival. It can 
also be that because of the abundance of food more offspring is 
produced than in 'colder' regions, but I honestly do not know if 
tropical birds have larger clutchsizes than other birds. That could 
lessen the need for migration.
Maybe the surroundings allow for more and better hiding places and 
camouflage  making it more difficult for predators to actually find the prey.
Maybe some other listmembers have some ideas about this too. This is, 
in my humble opinion, an interesting topic. Understanding the reasons 
for migration might give some insights into the possibilities of 
dinosaur migrations.


> 
>