Teresa Michelsen wrote:

> I'd like to add my two cents, esp. on Dennis' comments.
> Don't forget that a visually identifiable trait that occurs
> in many related birds may have no function whatsoever, but
> may have originally occurred as a random mutation and been
> propogated to offspring simply because it is LINKED with
> (e.g., physically located next to) a gene on a chromosome
> that does have an important function and is selected for.


What are the envirnmental pressures, ie, habitat choices, behaviour,
migratory strategies, etc among the vireos. If some sort of
classification/categorisation can be found and then the existance or not of
wing bars or any other feature can be tested.

I think it is all to easy to dismiss features/functions as genetic anomalies,
especially when discovering the reason why the feature/function maybe being
selected for is incredibly difficult. No harm in trying though.


Stuart MacKay