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Re: Megapodes!




On Thu, 21 Jun 2001, Chris Collinson wrote:

> However, they do not 
> simply semi abandon them until hatching in the manner of crocodilians, but 
> rather hang around (both parents) in order to regulate the temperature by 
> removing or adding material to the nest. They also  need to chase off the 
> large monitor lizards and snakes which have a fondness for megapode eggs. 
> They accomplish this feat by kicking vegetation at the foe.
> 
> For more Information, Check ot this webpage on the Australian Brush turkey, 
> Alectura lathami,
> at: http://www.ens.gu.edu.au/pggoeth/main.html

Thanks for this great website!  One of the abstracts talks about an innate
response of chicks (which, of course, are completely on their own) to the
alarm calls of other birds.  One other thing, nest defense to the
exclusion of concealment (i.e., when it's the primary mode of
protection) is extremely rare except, 1) on islands where the predators
are of similar size; 2) megapodes and crocs--crocs we
know, megapodes are as far as I know, the only birds to rely on obligatory
nest defense.  However, its success may be conditional on the make up of
resident predatory guilds.  In Australia the birds are known to fly great
distances inland--this may be a strategy for reducing the amount and
quality of predators.  In the islands of the South Pacific, megapodes
appear successful only on islands without Asian fauna--specifically,
cats.  I know we've been through this before...but I wouldn't want anyone
to get the impression that obligatory nest defense is a widely practiced.