[Tweeters] "half male/half female" Rose-breasted Grosbeak (gynandromorph)

[Diane Whitman]

Hello All,

Thought you might enjoy this rarity.  It was seen (and photographed)  
several times on May 9th by a number of birders at Presqu'ile  
Provincial Park (on the shore of Lake Ontario.)  If this link doesn't  
work directly, try   http://www.ofo.ca/photos/   and go to May 2007.   
Cool bird, eh!

9 May  
2007                                                                     
                                                 Rose-breasted  
Grosbeak that is all male on the right side and all female on the left.
This condition, known as a gynandromorph, is quite rare in birds but  
has been                                        described a few times  
in Evening Grosbeaks.  The bird is a "second-year"  
based                                      on the brownish primaries,  
and is fairly splotchy all over.  The split-sex effect
is most obvious from front-on, and looks like a male and female were  
cut in half                                     and pasted together  
to make a composite "frankenbeak."


Rose-breasted Grosbeak (gynandromorph) (Pheucticus ludovicianus)  May  
9.  Presqu'ile Provinical Park.  A gynandromorph is a rare condition  
where the bird shows both male and female characters.  Most  
gynandromorphs have a mixed male and female plumage.  This male Rose- 
breasted Grosbeak is the rarer bilateral type (more or less) with one  
half male and the other half female.  Photo by Bill Gilmour,  
<bill.gilmour AT sympatico DOT ca>

***********************************************************************
Diane Whitman
mszorro at gmail.com

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