QUESTION:
Are the orange and yellow colors on the Emperor penguins 
caused by the sun or are they natural?      


        Jonathan C.
        Mrs. Garvin's Class
        Mauldin Elementary
        Mauldin, SC



ANSWER from Steve Emslie, Researcher 
            Palmer Station, Antarctica
            Fri, 21 Mar 1997 15:17:29 -0500

Hello Jonathan,

Most colors of bird feathers are the result of pigments found
within the feather and are therefore natural.  These pigments 
act to absorb certain wavelengths of sunlight, and reflect others, 
and it is the reflected light that determines the color that we see.  
However, some feathers also have a specific microstructure with 
the pigment that causes the sun's rays to be absorbed or reflected 
and produce their color in that manner.  Blue and red colors, for 
instance, require direct sunlight to be recognizable.  If you ever see 
a male hummingbird with a red throat move into the shade, you 
will see that it appears dark or black instead.  A blue jay loses its 
brightness the same way.  The colors of the Emperor penguin, however, 
are based on pigments and do not need direct sunlight to be apparent, 
though the sun will enhance the colors so that they appear more brilliant.

Steve Emslie