Here's an interesting report on a study that entailed (no pun intended) 
putting Anna's Hummingbirds in a wind tunnel with "extensions" glued to 
their own tail feathers:
http://esciencenews.com/articles/2009/03/12/long.sexy.tails.not.a.drag.male.birds

Ah, science.

Janet Millenson
Potomac, MD (Montgomery County)

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"Look at the birds!" -- Pascal the parrot