Playing Devil's Advocate here?.
What if, instead of the elaborate model of the fitness of various breeding
populations that Simon outlined, the truth was that all members of a species
that attain adulthood are at a similar level of fitness, and whether they
succeed in breeding, or survive at all, is simply a matter of luck, or
unluck?
For example the hail-storm that killed all those Terns, what greater fitness
or adaptation, either in behaviour or physiology, could some birds have had
that would have allowed them to survive the hail-storm, that would not, in
some other stochastic instance, in the long-term, be deleterious to them or
their descendents?
In this case all the research of the type advocated by Simon and others
would do little good, as the only thing that will give a species a chance of
perpetuating itself is sufficient habitat, and sufficient respite from
disturbance.
Oh, and the reasoning behind Marilyn's assumption that banding was harmful
to the Little Terns is quite understandable:
1. Eight terns out of 30 whatever is a significant proportion;
2. Many more Little Terns are not banded than banded;
3. Therefore a greater proportion of those Terns that were banded were
killed compared to those that were not.
Point 2 may be wrong, but the reasoning is not.
John Leonard
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John Leonard (Dr)
http://users.bigpond.com/john.leonard
PO Box 243, Woden, ACT 2606, Australia
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