According to the BNA account for white-winged crossbill, "the lower 
mandible crosses to right approximately 3 times more often than to left." 

Interesting!

Kathy Fleming
Annapolis




Rick Sussman <> 
Sent by: Maryland Birds & Birding <>
02/12/2009 02:28 PM
Please respond to



To

cc

Subject
Re: [MDOSPREY] Centennial xbills






 
In a message dated 2/12/2009 8:07:04 A.M. Eastern Standard Time, 
 writes:

http://www.pbase.com/wcbirding/image/109116810



Mark's (excellent) photos also show something else that I have wondered 
about for years. Do crossbills bill always cross in the same direction. I 
know  we 
had this discussion about 11 years ago too. Well, Marks first 2 photos 
clearly show that the females (in his photo, not females in general I 
don't  think) 
bill crosses in the opposite direction than the second photo of the male. 
So, why? Unless he transposed some of the pictures...

Do ones whose bills cross one way feed differently from the others, ie; 
would it take seeds from cones in the opposite direction or side, and what 
if  any 
advantage would this make? Perhaps a small flock could take better 
advantage 
of a cone crop this way, by not missing as many seeds?
 
As always, more questions than answers...
 
Rick Sussman
Woodbine,MD
**************Nothing says I love you like flowers! Find a florist near 
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