RE: Herbivore protection

[Nathan Myhrvold <nathanm@MICROSOFT.com>]

Predator satiation is distinct from colonial nesting.   

It is possible for a population to use the same spot to nest, even
though they do not all lay eggs simultaneously. Conversely, it is
possible to lay eggs or give birth at the same moment in time, even if
you are not in a dense colony.    Most predator satiation is about
timing.

In some species, timing & density are linked, and in others they are
not.   

It seems likely for other reasons that Maiasaurs did do both - i.e.
occupy a dense colony, and also do it all roughly at the same time.  The
timing comes from how far north Montana is - it is not the sort of place
to lay eggs all year round, and although it was somewhat warmer then,
the seasonal variation was still pretty wide.  

I certainly wasn't suggesting that they nest closely ONLY for predator
satiation, but it is likely to be an effect - more for the hatchlings
running around for the first time than for the eggs themselves.   Eggs
could be guarded, and may well have been.

Nevertheless predator satiation of some form is highly likely to be part
of the mix. 

Nathan