color preferences of birds and insects

Adam Fikso
Thu, 05 Oct 2006 10:01:21 PDT
Ken, I note that you are a good observer.  Nectar quantity is a major 
consideration. One of the problems with big tubular red flowers is that they 
may have already been emptied by previous visitors, or, already checked by 
the hummingbird you were watching, or the nectar production is temperature 
and time of day  related. S/he may have known already that there was nothing 
in there any more.  Why go to a bottle that's been emptied ? 

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